Derivatives - Derivative Assets And Collateral Received (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Gross amounts of recognized assets	$ 695,853	$ 182,984
Derivative liabilities available for offset	0	0
Net amount	695,853	182,984
Derivative liabilities available for offset	(91,764)	(18,896)
Collateral received	(357,816)	(145,334)
Net amount	246,273	18,754
Derivative assets not subject to master netting agreements	400	100
Derivatives, interest rate contracts
Derivative [Line Items]
Gross amounts of recognized assets	530,337	162,344
Derivative liabilities available for offset	0	0
Net amount	530,337	162,344
Derivative liabilities available for offset	(1,974)	(5,604)
Collateral received	(303,798)	(143,334)
Net amount	224,565	13,406
Forward Contracts
Derivative [Line Items]
Gross amounts of recognized assets	165,516	20,640
Derivative liabilities available for offset	0	0
Net amount	165,516	20,640
Derivative liabilities available for offset	(89,790)	(13,292)
Collateral received	(54,018)	(2,000)
Net amount	$ 21,708	$ 5,348