Derivative Instruments, Offsetting Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	$ 899,319	$ 1,158,467
Gross amounts offset in the consolidated balance sheet	(1,352)	(2,611)
Net amounts of liabilities presented in the consolidated balance sheet	897,967	1,155,856
Gross amounts not offset in the consolidated balance sheet in financial instruments	(889,361)	(1,111,499)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	(8,606)	(44,357)
Net amount	0	0
Repurchase Agreements [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	897,047	1,149,978
Gross amounts offset in the consolidated balance sheet	0	0
Net amounts of liabilities presented in the consolidated balance sheet	897,047	1,149,978
Gross amounts not offset in the consolidated balance sheet in financial instruments	(888,441)	(1,105,621)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	(8,606)	(44,357)
Net amount	0	0
Interest Rate Swaps [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	896	5,878
Gross amounts offset in the consolidated balance sheet	0	0
Net amounts of liabilities presented in the consolidated balance sheet	896	5,878
Gross amounts not offset in the consolidated balance sheet in financial instruments	(896)	(5,878)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0	0
Net amount	0	0
TBAs [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	1,352	2,611
Gross amounts offset in the consolidated balance sheet	(1,352)	(2,611)
Net amounts of liabilities presented in the consolidated balance sheet	0	0
Gross amounts not offset in the consolidated balance sheet in financial instruments	0	0
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0	0
Net amount	0	$ 0
U.S. Treasury Futures [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	24
Gross amounts offset in the consolidated balance sheet	0
Net amounts of liabilities presented in the consolidated balance sheet	24
Gross amounts not offset in the consolidated balance sheet in financial instruments	(24)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0
Net amount	$ 0

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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