Fair Value - Level 3 Unobservable Inputs, Mortgage Loans and IRLC (Details) $ in Thousands	Jun. 30, 2021 USD ($) item	Dec. 31, 2020 USD ($) item
Excess servicing spread financing
Loans held for sale | $	$ 10,884,506	$ 11,616,400
Level 3
Excess servicing spread financing
Loans held for sale | $	$ 3,818,261	$ 4,675,169
Loans held for sale | Discount rate | Level 3 | Minimum
Excess servicing spread financing
Input	2.0	2.8
Loans held for sale | Discount rate | Level 3 | Maximum
Excess servicing spread financing
Input	9.2	9.2
Loans held for sale | Discount rate | Level 3 | Weighted average
Excess servicing spread financing
Input	2.0	2.8
Loans held for sale | Twelve-month projected housing price index Change | Level 3 | Minimum
Excess servicing spread financing
Input	4.8	2.7
Loans held for sale | Twelve-month projected housing price index Change | Level 3 | Maximum
Excess servicing spread financing
Input	5.3	3.5
Loans held for sale | Twelve-month projected housing price index Change | Level 3 | Weighted average
Excess servicing spread financing
Input	5.1	3.0
Loans held for sale | Prepayment/resale speed | Level 3 | Minimum
Excess servicing spread financing
Input	0.4	0.4
Loans held for sale | Prepayment/resale speed | Level 3 | Maximum
Excess servicing spread financing
Input	26.8	31.3
Loans held for sale | Prepayment/resale speed | Level 3 | Weighted average
Excess servicing spread financing
Input	22.0	21.9
Loans held for sale | Total prepayment speed | Level 3 | Minimum
Excess servicing spread financing
Input	0.4	0.5
Loans held for sale | Total prepayment speed | Level 3 | Maximum
Excess servicing spread financing
Input	37.6	42.9
Loans held for sale | Total prepayment speed | Level 3 | Weighted average
Excess servicing spread financing
Input	28.8	29.2
Interest rate lock commitments | Level 3
Excess servicing spread financing
Loans held for sale | $	$ 343,610	$ 677,026
Interest rate lock commitments | Pull-through rate | Level 3 | Minimum
Excess servicing spread financing
Input	8.0	10.1
Interest rate lock commitments | Pull-through rate | Level 3 | Maximum
Excess servicing spread financing
Input	100	100
Interest rate lock commitments | Pull-through rate | Level 3 | Weighted average
Excess servicing spread financing
Input	82.7	82.7
Interest rate lock commitments | Mortgage servicing rights value expressed as servicing fee multiple | Level 3 | Minimum
Excess servicing spread financing
Input	(14.7)	0.7
Interest rate lock commitments | Mortgage servicing rights value expressed as servicing fee multiple | Level 3 | Maximum
Excess servicing spread financing
Input	6.5	5.3
Interest rate lock commitments | Mortgage servicing rights value expressed as servicing fee multiple | Level 3 | Weighted average
Excess servicing spread financing
Input	3.6	3.6
Interest rate lock commitments | Percentage of unpaid principal balance | Level 3 | Minimum
Excess servicing spread financing
Input	(2.1)	0.1
Interest rate lock commitments | Percentage of unpaid principal balance | Level 3 | Maximum
Excess servicing spread financing
Input	3.1	2.6
Interest rate lock commitments | Percentage of unpaid principal balance | Level 3 | Weighted average
Excess servicing spread financing
Input	1.2	1.2