| Proceeds from Short-Term Debt | — | — | $20.5B | $22.8B | — | — | $46.6B | $51.4B |
| Repayments of Short-Term Debt | — | — | $20.4B | $22.1B | — | — | $44.4B | $44.2B |
| Payments To Acquire Trading Securities Heldforinvestment | $501.9M | $932.7M | $437.8M | $957.1M | $1.7B | $3.5B | $2.8B | $8.5B |
| Cash Provided by (Used in) Financing Activity, Including Discontinued Operation | $307.6M | $953.8M | $168.9M | $868.5M | $1.6B | $3.3B | $2.5B | $7.5B |
| Cash Provided by (Used in) Investing Activity, Including Discontinued Operation | -$335.3M | -$955.2M | $0 | -$908.4M | -$1.5B | -$3.3B | -$2.4B | -$7.2B |
| Proceeds From Sale Of Trading Securities Heldforinvestment | $3.4M | $3.4M | $3.4M | $0 | $0 | $0 | $0 | $633.3M |
| Principal payments received on trading securities | $107.9M | $119.3M | $134.5M | $120.9M | $186.4M | $232.8M | $292.7M | $453.3M |
| Proceeds from Issuance of Common Stock | $124.8M | $56.2M | $64.4M | $239.7M | $282.1M | $254.1M | $393.3M | $441.7M |
| Issuance of common stock in connection with the Spin-Off and reclassification of net parent investment | $124.8M | $56.2M | $64.4M | $239.7M | $282.1M | $254.1M | $393.3M | $441.7M |
| Net Change in Cash and Restricted Cash | — | — | $215.9M | -$33.5M | $117.8M | $118M | $106.6M | $359.3M |
| Noncash Or Part Noncash Acquisition Investments Acquired1 | — | — | $168.5M | $325.4M | — | — | $546M | $347.1M |
| Interest Income Operating | $76.1M | $83.5M | $88.5M | $95.1M | $111.7M | $149.7M | $177M | $257.4M |
| Payments for (Proceeds from) Derivative Instrument, Investing Activities | -$14.9M | — | -$325M | $137M | $64.1M | $32.6M | — | -$169M |
| Interest Paid, Net | $55.9M | $88.6M | $85.5M | $75.7M | $74.6M | $69.4M | $148.9M | $141.9M |
| Interest Paid, Excluding Capitalized Interest, Operating Activity | $55.9M | $88.6M | $85.5M | $75.7M | $74.6M | $69.4M | $148.9M | $141.9M |
| Dividends, Common Stock, Cash | $26.8M | $30.2M | $35.6M | $43.9M | $59.3M | $71.3M | $82.6M | $104.6M |
| Payments of Dividends | $27M | $31.2M | $34.8M | $41.6M | $56.6M | $69.6M | $78.8M | $102.5M |
| Cash Dividends Paid | $27M | $31.2M | $34.8M | $41.6M | $56.6M | $69.6M | $78.8M | $102.5M |
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | -$12M | $70.7M | $12.6M | $14.4M | -$12.2M | $162.5M | $189.6M | -$83.2M |
| Other Comprehensive Income (Loss) | -$12M | $70.7M | $12.6M | $14.4M | -$12.2M | $162.5M | $189.6M | -$83.2M |
| Reclassifications Net of Tax | -$10.2M | $29.1M | $49.2M | -$5M | -$16.3M | $147.6M | $182.6M | -$83M |
| Interest Income (Expense), Operating | $1.3M | $894K | $6.9M | $17.1M | $23.1M | $30.6M | $43.5M | $79.3M |
| Cash Provided by (Used in) Operating Activity, Including Discontinued Operation | $18.6M | -$2.3M | $15.1M | $6.4M | $31.9M | $68.3M | $14.3M | $69.8M |
| Increase Decrease In Interest Payable Net | $18.9M | -$6M | -$3.9M | $2.2M | $14M | $49.7M | — | $36.2M |
| Increase Decrease In Accrued Interest Receivable Net | $424K | $3.1M | $780K | $3.8M | $6.6M | $12.6M | $12M | $29.5M |
| Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale | $19.1M | $19.1M | $18M | $60M | $20.4M | $23.6M | $15.9M | $18M |
| Increase (Decrease) in Other Operating Assets and Liabilities, Net | $7.7M | -$1.5M | -$11.1M | $7.5M | — | — | -$4.4M | $9M |
| Debt and Equity Securities, Realized Gain (Loss) | -$1.5M | — | — | $0 | $0 | $0 | $0 | $8.7M |
| Realized gain | -$1.5M | $0 | $0 | $0 | $0 | $0 | $0 | $8.7M |
| Net realized gain on sale of marketable equity securities | — | — | — | $0 | — | — | — | $8.7M |
| Collateral received | — | -$11.5M | -$7.9M | $4.8M | $24.5M | — | — | -$8.4M |
| Issuance of Common Stock (Employee Equity Plans) | $724K | $779K | $1.1M | $2M | $3.4M | $2.7M | $4.2M | $7.7M |
| Stock-based compensation | $1M | $1M | $1.1M | $2M | $3M | $3M | $4.2M | $7.7M |
| Other General and Administrative Expense | $3.4M | $3.7M | $3.3M | $3.8M | $3.9M | $4.1M | $4.5M | $5.2M |
| Share-Based Payment Tax Withholding Decrease | — | $422K | — | $1.2M | $0 | $441K | $7K | $2.4M |
| Tax Withholding for Share-Based Payments | $0 | $421K | $1K | $1.2M | $0 | $441K | $7K | $2.4M |
| Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation | — | $422K | — | $1.2M | $0 | $441K | $7K | $2.4M |
| Payment, Tax Withholding, Share-Based Payment Arrangement | $0 | $421K | $1K | $1.2M | $0 | $441K | $7K | $2.4M |
| Stock options excluded as their inclusion would be anti-dilutive (in shares) | $1.1M | — | — | $547.8K | $687.6K | — | — | $1.3M |
| Other income, net | -$601K | -$436K | -$446K | -$354K | -$380K | -$534K | -$271K | -$775K |
| Other Depreciation and Amortization | $424K | $433K | $509K | $496K | $516K | $544K | $542K | $545K |
| OCI Unrealized Holding Gain (Loss) on Securities, Net of Tax | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| Unrealized Gain (Loss) on Securities | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| Other comprehensive income (loss), after-tax | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| OCI Unrealized Holding Gain (Loss) on Securities, Net of Tax | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| Other comprehensive income (loss) | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| Net unrealized gains (losses) on securities still held | -$1.8M | $41.7M | -$36.6M | $19.4M | $4.1M | $15M | $7M | -$148K |
| Equity issuance costs | $191K | $50K | $31K | $19K | $42K | $152K | $18K | $139K |
| Payments Of Stock Issuance Costs | $57.8K | $57.8K | $57.8K | $0 | — | — | — | $120K |
| Repayments and sales of loans | $134K | $224K | $97K | $67K | $57K | $92K | $333K | $17K |
| Number of Operating Segments | 0.25 | 0.25 | 0.25 | 1.00 | — | — | — | 1.00 |
| Number of operating segments | $0.3 | $0.3 | $0.3 | $1 | — | — | — | $1 |
| Common Stock Dividends Per Share Declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Common Stock Dividends Per Share | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Dividends per share declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Dividends per share declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Common Stock Dividends Per Share Declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Dividends declared (in dollars per share) | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Common Stock Dividends Per Share Declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Common Stock Dividends Per Share Declared | — | $0.4 | $0.4 | $0.5 | $0.5 | $0.5 | $0.5 | $0.5 |
| Debt Securities, Trading, Realized Loss | $1.5M | $0 | $0 | $0 | $0 | $0 | $0 | $0 |
