Fair Value Fair Value (Assets and liabilities measured at fair value on a nonrecurring basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	$ 6,844,788	$ 7,112,474
Other Assets, Fair Value Disclosure	6,834,592	7,072,339
Other Repossessed Assets	3,600	3,600
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	9,348	33,211
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	6,835,440	7,079,263
Other Assets, Fair Value Disclosure	6,834,592	7,072,339
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	848	6,924
Servicing Asset at Fair Value, Amount	14,286	12,179
Other Assets, Fair Value Disclosure	735	735
Other Repossessed Assets	3,164	3,164
Fair Value, Nonrecurring [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	277	175
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset at Fair Value, Amount	14,286	12,179
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	848	6,924
Other Assets, Fair Value Disclosure	735	735
Other Repossessed Assets	3,164	3,164
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	277	175
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	571	6,749
Commercial Real Estate Portfolio Segment [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	571	6,749
Residential Real Estate [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	735	735
Residential Real Estate [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets, Fair Value Disclosure	735	735
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	6,820,288	7,092,110
Other Assets, Fair Value Disclosure	$ 6,810,092	$ 7,051,975