Assets Purchased under Resale Agreements and Sold under Repurchase Agreements (Resale Agreements and Repurchase Agreements) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Resale agreements
Gross resale agreements	$ 1,330,000		$ 1,330,000
Loans purchased under agreements to resell	621,800		1,020,000
Repurchase agreements
Gross repurchase agreements	$ 300,000		$ 300,000
Weighted average interest rates	2.62%	2.67%
Securities Purchased Under Resale Agreements
Resale agreements
Weighted-average yields	1.63%	1.57%
Loans Purchased Under Resale Agreements
Resale agreements
Weighted-average yields	1.60%	2.02%