Derivative Activities - Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative assets:
Derivative asset, before netting	$ 398,672	$ 847,831
Netting	(64,977)	(136,593)
Total derivative assets	333,695	711,238
Derivative liabilities:
Derivative liability, before netting	54,702	255,360
Netting	(32,096)	(212,722)
Net amounts of liabilities presented in the consolidated balance sheet	22,606	42,638
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Gains (losses) recognized on derivative financial instruments	(475,215)	918,180	$ 395,497
Interest Expense. | Repurchase agreement derivative
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Gains (losses) recognized on derivative financial instruments		83	(1,609)
Net gains on loans held for sale at fair value | Interest rate lock commitments and loans held for sale
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Gains (losses) recognized on derivative financial instruments	319,141	(650,898)	(157,806)
Net loan servicing fees | Mortgage servicing rights
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Gains (losses) recognized on derivative financial instruments	(475,215)	918,180	395,497
Margin Deposits
Derivative assets:
Collateral placed with (received from) derivative counterparties	(32,881)	76,129
Interest rate lock commitments
Derivative assets:
Total derivative assets	323,473	679,961
Interest rate lock commitments | Net gains on loans held for sale at fair value
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Gains (losses) recognized on derivative financial instruments	(354,833)	540,376	$ 87,312
Not designated as hedging instrument | Interest rate lock commitments
Derivative Instruments
Notional amount	14,111,795	20,624,535
Derivative assets:
Derivative asset, before netting	323,473	679,961
Derivative liabilities:
Derivative liability, before netting	1,280	2,935
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	20,624,535
Balance at end of period	14,111,795	20,624,535
Not designated as hedging instrument | Forward contracts | Purchases
Derivative Instruments
Notional amount	22,007,383	31,689,543
Derivative assets:
Derivative asset, before netting	20,485	133,267
Derivative liabilities:
Derivative liability, before netting	18,007	1,276
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	31,689,543
Balance at end of period	22,007,383	31,689,543
Not designated as hedging instrument | Forward contracts | Sales
Derivative Instruments
Notional amount	34,429,676	50,438,967
Derivative assets:
Derivative asset, before netting	40,215	1,451
Derivative liabilities:
Derivative liability, before netting	35,415	251,149
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	50,438,967
Balance at end of period	34,429,676	50,438,967
Not designated as hedging instrument | MBS put options
Derivative Instruments
Notional amount	9,550,000	12,025,000
Derivative assets:
Derivative asset, before netting	7,655	14,302
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	12,025,000
Balance at end of period	9,550,000	12,025,000
Not designated as hedging instrument | Swaptions | Purchases
Derivative Instruments
Notional amount	5,375,000	3,375,000
Derivative assets:
Derivative asset, before netting	1,625	11,939
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	3,375,000
Balance at end of period	5,375,000	3,375,000
Not designated as hedging instrument | Put options on Eurodollar futures | Purchases
Derivative Instruments
Notional amount	2,450,000	4,750,000
Derivative assets:
Derivative asset, before netting	3,141	5,520
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	4,750,000
Balance at end of period	2,450,000	4,750,000
Not designated as hedging instrument | Call options on Eurodollar futures | Purchases
Derivative Instruments
Notional amount	1,250,000	850,000
Derivative assets:
Derivative asset, before netting	2,078	1,391
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	850,000
Balance at end of period	1,250,000	850,000
Not designated as hedging instrument | Treasury future | Purchases
Derivative Instruments
Notional amount	1,544,800	1,065,000
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	1,065,000
Balance at end of period	1,544,800	1,065,000
Not designated as hedging instrument | Treasury future | Sales
Derivative Instruments
Notional amount	1,925,000	1,555,000
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	1,555,000
Balance at end of period	1,925,000	1,555,000
Not designated as hedging instrument | Interest rate swap futures | Purchases
Derivative Instruments
Notional amount	3,010,600	4,801,700
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	4,801,700
Balance at end of period	3,010,600	4,801,700
Not designated as hedging instrument | Interest rate swap futures | Sales
Derivative Instruments
Notional amount	2,187,200	711,700
Activity for derivative contracts used to hedge the IRLCs and inventory of mortgage loans at notional value
Balance at beginning of period	711,700
Balance at end of period	$ 2,187,200	$ 711,700