Fair Value Measurements (Recurring) (Details) $ in Thousands	Mar. 31, 2018 USD ($) derivative	Dec. 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of interest rate derivatives | derivative	0
Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	$ (477)	$ 1,231
Derivative liabilities	(6,672)	(6,402)
Total net assets	(7,149)	(5,171)
Fair Value, Inputs, Level 2 | Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	(477)	1,231
Total net assets	(477)	1,231
Fair Value, Inputs, Level 3 | Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities	(6,672)	(6,402)
Total net assets	$ (6,672)	$ (6,402)