Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 771,511	$ 705,103	$ 746,961	$ 714,551
Current period other comprehensive (loss) income:
Total current period other comprehensive (loss) income		(1,971)	3,671	1,241	(7,616)
Balance		790,552	726,911	790,552	726,911
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(6,225)	(15,209)	(7,210)	(10,995)
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications		(2,872)	3,881	(1,722)	(940)
Effect of taxes	[1]	361	(714)	196	(107)
Total current period other comprehensive (loss) income		(2,511)	3,167	(1,526)	(1,047)
Balance		(8,736)	(12,042)	(8,736)	(12,042)
Gain on Sale of Interest Rate Hedge Agreement
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[2]	833	1,368	1,096	1,634
Current period other comprehensive (loss) income:
Amounts reclassified from accumulated other comprehensive (loss) income	[2],[3]	(180)	(180)	(540)	(540)
Effect of taxes	[1],[2]	48	47	145	141
Total current period other comprehensive (loss) income	[2]	(132)	(133)	(395)	(399)
Balance	[2]	701	1,235	701	1,235
Change in Fair Value of Interest Rate Hedge Agreements
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[4]	(5,502)	(9,590)	(7,992)	(2,783)
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications	[4]	(27)	(45)	1,530	(10,200)
Amounts reclassified from accumulated other comprehensive (loss) income	[3],[4]	943	909	2,778	1,832
Effect of taxes	[1],[4]	(244)	(227)	(1,146)	2,198
Total current period other comprehensive (loss) income	[4]	672	637	3,162	(6,170)
Balance	[4]	(4,830)	(8,953)	(4,830)	(8,953)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(10,894)	(23,431)	(14,106)	(12,144)
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications		(2,899)	3,836	(192)	(11,140)
Amounts reclassified from accumulated other comprehensive (loss) income	[3]	763	729	2,238	1,292
Effect of taxes	[1]	165	(894)	(805)	2,232
Total current period other comprehensive (loss) income		(1,971)	3,671	1,241	(7,616)
Balance		$ (12,865)	$ (19,760)	$ (12,865)	$ (19,760)

[1] The Company’s effective tax rate for the three months ended September 30, 2021 and 2020 was 31.6% and 27.2%, respectively

[2] Represents the unamortized value of an interest rate hedge agreement, designated as a cash flow hedge, which was sold on December 1, 2016. The fair value of the interest rate hedge agreement, at the date of the sale, was recorded in other comprehensive income, net of tax, and is being reclassified to interest expense when earnings are impacted by the hedged items and as interest payments are made on the Credit Facility from January 31, 2018 to January 31, 2023 (see Note 8—Derivative Instruments and Hedging Activities).

[3] The Company expects to reclassify $0.7 million net gains related to the Gain on Sale of Interest Rate Hedge Agreement and $3.7 million net losses related to the Change in Fair Value of Interest Rate Hedge Agreement from accumulated other comprehensive loss into earnings during the next 12 months

[4] Represents the change in fair value of interest rate hedge agreements designated as a cash flow hedge.  The fair value of the interest rate hedge agreements was recorded in other comprehensive income and will be reclassified to interest expense when earnings are impacted by the hedged items and as interest payments are made on the Credit Facility from August 31, 2018 to February 28, 2025 (see Note 8—Derivative Instruments and Hedging Activities).