Derivatives Pre-Tax Gains (Losses) (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]
Unrealized gain (loss) on interest rate cash flow hedges, pre-tax, accumulated other comprehensive income (loss)	$ (4,729)	$ 1,003	$ (7,170)	$ 2,548
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on interest rate cash flow hedges, pre-tax, accumulated other comprehensive income (loss)			(7,170)	2,548
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash flow hedge gain (loss) reclassified to interest expense, net			$ 204	$ 82