Derivative Financial Instruments - Summary of Fair Value of Derivative Financial Instruments, Excluding Adjustments for Performance Risk and Their Classification on Condensed Consolidated Balance Sheets (Details) - Interest Rate Swaps and Collars - Designated as Hedging Instrument - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Other Current Assets
Derivative [Line Items]
Fair value of derivative instruments, asset derivatives	$ 643	$ 1,936
Other Assets
Derivative [Line Items]
Fair value of derivative instruments, asset derivatives	96	$ 2,795
Other Current Liabilities
Derivative [Line Items]
Fair value of derivative instruments, liability derivatives	23
Other Liabilities
Derivative [Line Items]
Fair value of derivative instruments, liability derivatives	$ 207