Derivative Financial Instruments Income Statement Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net effect of swaps	$ 7,442	$ (45)	$ (1,197)
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amortization of Deferred Hedge Gains	9,459	9,459	8,671
Designated As Hedging [Member] | Interest Rate Swap [Member] | Net Effect of Swaps [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in income	$ (2,017)	$ (9,504)	$ (9,868)