Investments in Servicing Related Assets, Summary (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2022	Dec. 31, 2021
Servicing Asset [Abstract]
Unpaid principal balance		$ 20,441,178	$ 20,773,278
Carrying value	[1]	$ 246,103	$ 218,727
Weighted average coupon		3.48%	3.51%
Weighted average maturity	[2]	26 years 2 months 12 days	26 years 3 months 18 days
Year to date changes in fair value recorded in other income (loss)		$ 21,731	$ (11,062)
Mortgage Servicing Rights (MSRs) [Member]
Servicing Asset [Abstract]
Unpaid principal balance		20,441,178	20,773,278
Carrying value	[1]	$ 246,103	$ 218,727
Weighted average coupon		3.48%	3.51%
Weighted average maturity	[2]	26 years 2 months 12 days	26 years 3 months 18 days
Year to date changes in fair value recorded in other income (loss)		$ 21,731	$ (11,062)

[1] See Note 9 regarding the estimation of fair value, which approximates carrying value for all pools.

[2] Weighted average maturity of the underlying residential mortgage loans in the pool is based on the unpaid principal balance.