Derivative Instruments, Offsetting Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	$ 18,998	$ 18,581
Gross amounts offset in the consolidated balance sheet	(1,352)	(2,611)
Net amounts of assets presented in the consolidated balance sheet	17,646	15,970
Gross amounts not offset in the consolidated balance sheet in financial instruments	(16,434)	(14,001)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	(1,212)	(1,969)
Net amount	0	0
Interest Rate Swaps [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	15,164	10,791
Gross amounts offset in the consolidated balance sheet	0	0
Net amounts of assets presented in the consolidated balance sheet	15,164	10,791
Gross amounts not offset in the consolidated balance sheet in financial instruments	(15,164)	(10,791)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0	0
Net amount	0	0
Interest Rate Swaptions [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	1,516	798
Gross amounts offset in the consolidated balance sheet	0	0
Net amounts of assets presented in the consolidated balance sheet	1,516	798
Gross amounts not offset in the consolidated balance sheet in financial instruments	(1,516)	(798)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0	0
Net amount	0	0
TBAs [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	2,235	6,740
Gross amounts offset in the consolidated balance sheet	(1,352)	(2,611)
Net amounts of assets presented in the consolidated balance sheet	883	4,129
Gross amounts not offset in the consolidated balance sheet in financial instruments	(883)	(4,129)
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	0	0
Net amount	0	0
U.S. Treasury Futures Options [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	83
Gross amounts offset in the consolidated balance sheet	0
Net amounts of assets presented in the consolidated balance sheet	83
Gross amounts not offset in the consolidated balance sheet in financial instruments	1,129
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)	(1,212)
Net amount	$ 0
Treasury Futures [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets		252
Gross amounts offset in the consolidated balance sheet		0
Net amounts of assets presented in the consolidated balance sheet		252
Gross amounts not offset in the consolidated balance sheet in financial instruments		1,717
Gross amounts not offset in the consolidated balance sheet in cash collateral received (pledged)		(1,969)
Net amount		$ 0

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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