Assets Purchased under Resale Agreements and Sold under Repurchase Agreements (Balance Sheet Offsetting) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets, Resale Agreements
Gross Amounts of Recognized Assets	$ 1,956,822	$ 2,353,503
Gross Amounts Offset on the Consolidated Balance Sheet	0	0
Net Amounts of Assets Presented on the Consolidated Balance Sheet	1,956,822	2,353,503
Assets Purchased under Agreements to Resell Gross Amounts Not Offset [Abstract]
Collateral Received	(1,918,204)	(2,327,687)
Net Amount	38,618	25,816
Liabilities, Repurchase Agreements
Gross Amounts of Recognized Liabilities	300,000	300,000
Gross Amounts Offset on the Consolidated Balance Sheet	0	0
Net Amounts of Liabilities Presented on the Consolidated Balance Sheet	300,000	300,000
Assets Sold under Agreements to Repurchase Gross Amounts Not Offset [Abstract]
Collateral Pledged	(290,172)	(300,000)
Net Amount	$ 9,828	$ 0