Derivative Financial Instruments - Offsetting of Derivative Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	$ 125,157	$ 167,870
Gross amounts offset in the consolidated balance sheet	(98,016)	(136,593)
Net amounts of assets presented in the consolidated balance sheet	27,141	31,277
Total
Gross amounts of recognized assets	469,285	847,831
Net amounts of assets presented in the balance sheet	371,269	711,238
Interest rate lock commitments
Derivatives not subject to master netting arrangements
Gross amounts of recognized assets	344,128	679,961
Total
Net amounts of assets presented in the balance sheet	344,128	679,961
MBS put options
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	13,106	14,302
Net amounts of assets presented in the consolidated balance sheet	13,106	14,302
Total
Gross amounts of recognized assets	13,106	14,302
MBS call options
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	687
Net amounts of assets presented in the consolidated balance sheet	687
Total
Gross amounts of recognized assets	687
Swaptions | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	11,041	11,939
Net amounts of assets presented in the consolidated balance sheet	11,041	11,939
Total
Gross amounts of recognized assets	11,041	11,939
Forward contracts | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	55,765	133,267
Net amounts of assets presented in the consolidated balance sheet	55,765	133,267
Total
Gross amounts of recognized assets	55,765	133,267
Forward contracts | Sales
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	39,597	1,451
Net amounts of assets presented in the consolidated balance sheet	39,597	1,451
Total
Gross amounts of recognized assets	39,597	1,451
Put options on interest rate futures | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	2,664	5,520
Net amounts of assets presented in the consolidated balance sheet	2,664	5,520
Total
Gross amounts of recognized assets	2,664	5,520
Call options on interest rate futures | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	2,297	1,391
Net amounts of assets presented in the consolidated balance sheet	2,297	1,391
Total
Gross amounts of recognized assets	$ 2,297	$ 1,391