Offsetting of Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial derivatives–assets
Financial derivatives–assets, at fair value-	$ 65,082	$ 18,894
Financial Instruments Available for Offset	(15,656)	(9,909)
Cash Collateral (Received) Pledged	(18,080)	(1,720)
Net Amount	31,346	7,265
Reverse repurchase agreements
Reverse repurchase agreements	131,243	123,250
Financial Instruments Available for Offset	(54,344)	(123,250)
Cash Collateral (Received) Pledged	0	0
Net Amount	0	0
Repurchase agreements
Reverse repurchase agreements	(2,717,638)	(2,469,763)
Financial Instruments Available for Offset	54,344	2,469,763
Cash Collateral (Received) Pledged	100,806	70,314
Net Amount	0	0
Financial derivatives–liabilities
Financial derivatives–liabilities, at fair value-	(16,528)	(12,298)
Financial Instruments Available for Offset	15,656	9,909
Cash Collateral (Received) Pledged	648	2,169
Net Amount	(224)	(220)
Securities Collateral relating to Reverse Repurchase Agreements	3,100,000	2,800,000
Financial Derivatives - Assets
Financial derivatives–assets
Financial Instruments Transferred or Pledged as Collateral	0	0
Financial derivatives–liabilities
Excess cash collateral	1,300	10,700
Securities Purchased under Agreements to Resell [Member]
Financial derivatives–assets
Financial Instruments Transferred or Pledged as Collateral	76,899	0
Financial Derivatives - Liabilities
Financial derivatives–assets
Financial Instruments Transferred or Pledged as Collateral	0	0
Financial derivatives–liabilities
Excess cash collateral	2,000	2,000
Reverse repurchase agreements
Financial derivatives–assets
Financial Instruments Transferred or Pledged as Collateral	$ 2,562,488	$ (70,314)