Derivatives - Derivative Assets And Collateral Received (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Net amount	$ 250,786	$ 81,475
Derivative assets not subject to master netting agreements	35,700	28,900
Derivatives, interest rate contracts
Derivative [Line Items]
Gross amounts of recognized assets	215,085	52,562
Derivative liabilities available for offset	0	0
Net amount	215,085	52,562
Derivative liabilities available for offset	(2,957)	(12,745)
Collateral received	(162,303)	(39,637)
Net amount	$ 49,825	$ 180