Offsetting of Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 1,732
Derivative Asset, Fair Value, Gross Liability	0
Financial derivatives–assets, at fair value	1,732	$ 4,180
Reverse repurchase agreements	2,218	2,084
Financial derivatives–liabilities, at fair value	(20,234)	(2,047)
Repurchase agreements	(1,109,342)	(1,296,272)
Derivative Liability, Fair Value, Amount Offset Against Collateral	(1,276)	(1,756)
Securities sold under agreements to repurchase available for offset	(2,218)	(2,084)
Derivative Asset, Fair Value, Amount Offset Against Collateral	1,276	1,756
Securities purchased under agreements to resell available for offset	2,218	2,084
Derivative, Collateral, Obligation to Return Cash	0	0
Cash collateral received	0	0
Derivative, Collateral, Right to Reclaim Cash	18,334	211
Cash Collateral Pledged	20,470	24,924
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	456	2,424
Securities Purchased under Agreements to Resell, Gross	28,288
Securities Purchased under Agreements to Resell, Liability	(26,070)
Reverse Repurchase Agreements and Related Collateral Net	0	0
Derivative Liability, Fair Value, Gross Liability	(20,234)
Derivatives and related collateral, net	(624)	(80)
Securities Sold under Agreements to Repurchase, Gross	(1,135,412)
Securities Sold under Agreements to Repurchase, Asset	26,070
Repurchase agreements and related collateral, net	0	0
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	1,200,000	1,300,000
Derivative Financial Instruments, Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Excess cash collateral	300	8,300
Derivative Financial Instruments, Liabilities [Member]
Offsetting Assets and Liabilities [Line Items]
Excess cash collateral	8,200	1,100
Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Financial Instruments Pledged as Collateral	1,086,654	1,269,264
Reverse Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Financial Instruments Pledged as Collateral	0	0
Derivative Financial Instruments, Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Financial Instruments Pledged as Collateral	0	0
Derivative Financial Instruments, Liabilities [Member]
Offsetting Assets and Liabilities [Line Items]
Financial Instruments Pledged as Collateral	$ 0	$ 0

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[Line Items] for Offsetting of Assets and Liabilities [Table]

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