Derivative Activities - Offsetting of Derivative Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivatives not subject to master netting arrangements
Gross amounts of recognized assets	$ 146,698	$ 77,277
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	40,699	46,039
Gross amounts offset in the consolidated balance sheet	(27,711)	(26,969)
Net amounts of assets presented in the consolidated balance sheet	12,988	19,070
Total
Gross amounts of recognized assets	187,397	123,316
Net amounts of assets presented in the balance sheet	159,686	96,347
Interest rate lock commitments
Derivatives not subject to master netting arrangements
Gross amounts of recognized assets	138,511	50,507
Total
Net amounts of assets presented in the balance sheet	138,511	50,507
Repurchase agreement derivatives
Derivatives not subject to master netting arrangements
Gross amounts of recognized assets	8,187	26,770
MBS put options
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	3,415	720
Net amounts of assets presented in the consolidated balance sheet	3,415	720
MBS call options
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets		2,135
Net amounts of assets presented in the consolidated balance sheet		2,135
Swaptions
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	2,409
Net amounts of assets presented in the consolidated balance sheet	2,409
Forward contracts | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	12,364	35,916
Net amounts of assets presented in the consolidated balance sheet	12,364	35,916
Forward contracts | Sales
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	17,097	437
Net amounts of assets presented in the consolidated balance sheet	17,097	437
Put options on interest rate futures | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	3,945	866
Net amounts of assets presented in the consolidated balance sheet	3,945	866
Call options on interest rate futures | Purchases
Derivatives subject to master netting arrangements:
Gross amounts of recognized assets	1,469	5,965
Net amounts of assets presented in the consolidated balance sheet	$ 1,469	$ 5,965