Derivative Instruments - Volume of Activity, in terms of Notional Amount, Related to Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivative [Line Items]
Beginning of Period	$ 155,000	$ 0	$ 0
Additions	535,000	1,125,000	1,290,000	$ 2,490,000
Scheduled Settlements	435,000	1,100,000	1,035,000	2,465,000
Early Terminations	0	0	0	0
End of Period	255,000	25,000	255,000	25,000
Interest Rate Swap
Derivative [Line Items]
Beginning of Period	230,000	525,000	150,000	275,000
Additions	90,000	0	235,000	450,000
Scheduled Settlements	0	0	0	0
Early Terminations	(125,000)	(310,000)	(190,000)	(510,000)
End of Period	195,000	215,000	195,000	215,000
2-year U.S. Treasury Note Futures
Derivative [Line Items]
Beginning of Period				0
Additions				50,000
Scheduled Settlements				(50,000)
Early Terminations				0
End of Period		0		0
10-year U.S. Treasury Note Futures
Derivative [Line Items]
Beginning of Period		45,000	25,000	0
Additions		0	50,000	540,100
Scheduled Settlements		(45,000)	(50,000)	(365,000)
Early Terminations		0	(25,000)	(175,100)
End of Period	0	0	0	0
Purchased Call Options on Ten Year U.S. Treasury Note Futures
Derivative [Line Items]
Beginning of Period			25,000	0
Additions			0	65,200
Scheduled Settlements			(25,000)	(65,200)
Early Terminations			0	0
End of Period	$ 0	$ 0	$ 0	$ 0