Investments - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended			12 Months Ended
	Mar. 31, 2020	Mar. 31, 2022 USD ($) security	Mar. 31, 2022 USD ($) security	Mar. 31, 2022 USD ($) security Rate	Dec. 31, 2021 USD ($) security
Investments, Debt and Equity Securities [Abstract]
Vertical risk retention interest	5.00%		5.00%	5.00%
Trading investments		$ 38,820	$ 38,820	$ 38,820	$ 37,465
Number of available-for-sale securities with unrealized losses | security		158	158	158	60
Number of available-for-sale securities | security		186	186	186	180
Par value of mortgage-backed securities pledged to FRB		$ 720,000	$ 720,000	$ 720,000	$ 888,000
Non-marketable securities investment		69,000	69,000	69,000	69,000
Low income housing tax credit investments		66,000	66,000	66,000	68,000
Low income housing tax credit investments, liability for unfunded commitments		28,000	$ 28,000	$ 28,000	30,000
Low income housing tax credit investments, tax credits and benefits (current year less than)		$ 1,000			$ 7,000
Low income housing tax credit investments, expected tax benefits recognized			25.00%