Summary of Significant Accounting Policies - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Accumulated Other Comprehensive Loss [Line Items]
Accumulated other comprehensive loss	$ (21,602)	$ (10,359)	$ (13,805)
AOCI Attributable to Parent
Accumulated Other Comprehensive Loss [Line Items]
Accumulated other comprehensive loss	(21,602)	(10,359)	(13,805)
Foreign currency translation adjustments
Accumulated Other Comprehensive Loss [Line Items]
Accumulated other comprehensive loss	(10,447)	(10,127)	(13,156)
Unrealized (losses) gains on interest rate swaps, net of tax
Accumulated Other Comprehensive Loss [Line Items]
Accumulated other comprehensive loss	$ (11,155)	$ (232)	$ (649)