Derivatives - Gains/(Losses) on Derivatives Associated with Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) expected to be reclassified to earnings in the next twelve months			$ (300)
Hedging Instruments And Hedged Items
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss), cash flow hedges	$ 7,575	$ (3,457)	11,511	$ (12,095)
Gain/(loss) reclassified from AOCI into Interest income	1,334	463	2,785	308
Hedging Instruments And Hedged Items | Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss), cash flow hedges	$ 11,896	$ (3,914)	$ 19,114	$ (15,531)