Short-Term Debt - Maturities of Outstanding Advances Under Repurchase Agreements (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Mortgage loans sold under agreement to repurchase
Unpaid principal balance	$ 3,336,577
Weighted-average maturity (in months)	2 months 21 days
Within 30 days
Mortgage loans sold under agreement to repurchase
Unpaid principal balance	$ 1,154,865
Over 30 to 90 days
Mortgage loans sold under agreement to repurchase
Unpaid principal balance	1,712,249
Over 90 to 180 days
Mortgage loans sold under agreement to repurchase
Unpaid principal balance	358,203
Over 180 days to one year
Mortgage loans sold under agreement to repurchase
Unpaid principal balance	$ 111,260