Fair Value Measurements (Recurring) (Details) $ in Thousands	Jun. 30, 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	$ (3,676)	$ 1,231
Derivative liabilities	(7,926)	(6,402)
Total net assets	(11,602)	(5,171)
Fair Value, Inputs, Level 2 | Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	(3,676)	1,231
Total net assets	(3,676)	1,231
Fair Value, Inputs, Level 3 | Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liabilities	(7,926)	(6,402)
Total net assets	$ (7,926)	$ (6,402)