Derivative Financial Instruments - Offsetting of Derivative Assets - Derivative Assets, Financial Assets, and Collateral Held by Counterparty (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Total
Net amounts of assets presented in the balance sheet	$ 400,302	$ 159,686
Net amount	400,302	159,686
JP Morgan
Total
Net amounts of assets presented in the balance sheet	3,462	2,196
Net amount	3,462	2,196
RJ O'Brien
Total
Net amounts of assets presented in the balance sheet	3,711	5,414
Net amount	3,711	5,414
Deutsche Bank AG
Total
Net amounts of assets presented in the balance sheet	8,187	9,138
Net amount	8,187	9,138
Wells Fargo Bank, N.A.
Total
Net amounts of assets presented in the balance sheet	9,482
Net amount	9,482
Mizuho Securities
Total
Net amounts of assets presented in the balance sheet		1,597
Net amount		1,597
Goldman Sachs
Total
Net amounts of assets presented in the balance sheet	2,094	2,548
Net amount	2,094	2,548
Nomura Securities International, Inc.
Total
Net amounts of assets presented in the balance sheet	1,482
Net amount	1,482
Other
Total
Net amounts of assets presented in the balance sheet	2,429	282
Net amount	2,429	282
Interest rate lock commitments
Total
Net amounts of assets presented in the balance sheet	369,455	138,511
Net amount	$ 369,455	$ 138,511