Fair Value of Assets and Liabilities - Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Fair Value, Mortgage Servicing Rights, Beginning Balance	$ 875	$ 1,068	$ 958	$ 1,126
Fair Value, Mortgage Servicing Rights, Realized and Unrealized Net Gains (Losses) Included in Net Income	(49)	(50)	(132)	(108)
Fair Value, Mortgage Servicing Rights, Ending Balance	826	1,018	826	1,018
Fair Value, Mortgage Service Rights, Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held	0	0	0	0
Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation Roll Forward
Fair Value, Net Derivative Assets and Liabilities, Beginning Balance	37,957	88,995	77,880	22,573
Fair Value, Net Derivative Assets and Liabilities, Realized and Unrealized Net Gains (Losses) Included in Net Income	2,095	4,909	7,008	15,372
Fair Value, Net Derivative Assets and Liabilities, Transfers to Loans Held for Sale	(3,068)	(4,242)	(10,652)	(13,521)
Variation margin payments for swap liabilities	(5,875)	(1,840)	(43,127)	63,398
Fair Value, Net Derivative Assets and Liabilities, Ending Balance	31,109	87,822	31,109	87,822
Fair Value, Net Derivative Assets and Liabilities,Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held	$ 31,109	$ 87,822	$ 31,109	$ 87,822