Derivative Financial Instruments - Summary of Fair Value of Interest Rate Related Derivative Financial Instruments and Their Classification on Our Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Interest Rate Swaps and Collars | Designated as Hedging Instrument | Other Current Liabilities
Derivative [Line Items]
Fair value of derivative instruments, liability derivatives	$ 99	$ 1,626