Derivatives - Effect of Derivative Instruments on Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effect of derivative instruments on results of operations
Total amount of interest expense in which the effects of cash flow hedges are recorded	$ 25,778	$ 25,954	$ 55,443	$ 49,571
Interest Rate Swaps
Effect of derivative instruments on results of operations
Pre-tax loss recognized in other comprehensive income (loss)	(738)	(4,529)	(8,311)	(6,828)
Pre-tax gain (loss) reclassified from accumulated other comprehensive loss into interest expense	(1,073)	791	(1,322)	1,717
Total amount of interest expense in which the effects of cash flow hedges are recorded	$ 25,778	$ 25,954	$ 55,443	$ 49,571