Fair Value Measurements - Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets - interest rate swaps	$ 2,539	$ 1,592
Derivative liabilities - interest rate swaps	1,135	242
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative assets - interest rate swaps	2,539	1,592
Derivative liabilities - interest rate swaps	$ 1,135	$ 242