Derivative Activities - Offsetting of Derivative Assets - Derivative Assets, Financial Assets, and Collateral Held by Counterparty (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Total
Net amounts of assets presented in the balance sheet	$ 159,686	$ 96,347
Net amount		96,347
JP Morgan
Total
Net amounts of assets presented in the balance sheet	2,196	1,399
Net amount		1,399
Citibank, N.A.
Total
Net amounts of assets presented in the balance sheet		2,488
Net amount		2,488
RJ O'Brien
Total
Net amounts of assets presented in the balance sheet	5,414	6,831
Net amount		6,831
Deutsche Bank AG
Total
Net amounts of assets presented in the balance sheet	9,138	26,770
Net amount		26,770
Wells Fargo Bank, N.A.
Total
Net amounts of assets presented in the balance sheet		3,707
Net amount		3,707
Mizuho Securities
Total
Net amounts of assets presented in the balance sheet	1,597
Goldman Sachs
Total
Net amounts of assets presented in the balance sheet	2,548
Bank of America, N.A.
Total
Net amounts of assets presented in the balance sheet		2,781
Net amount		2,781
Other
Total
Net amounts of assets presented in the balance sheet	282	1,864
Net amount		1,864
Interest rate lock commitments
Total
Net amounts of assets presented in the balance sheet	$ 138,511	50,507
Net amount		$ 50,507