Other Comprehensive (Loss) Income and Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018		Dec. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 666,637	$ 635,371	$ 660,417		$ 616,030
Current period other comprehensive (loss) income:
Total current period other comprehensive (loss) income		(3,281)	(568)	(5,851)		(2,276)
Balance		685,502	650,673	685,502		650,673
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(14,055)	(11,074)	(14,168)		(7,638)
Reclassification of stranded tax effects due to adoption of accounting principle	[1]					(1,307)
Adjusted beginning balance								$ (8,945)
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications		(2,858)	(255)	(2,582)		(2,530)
Amounts reclassified from accumulated other comprehensive (loss) income		0
Effect of taxes	[2]	196	(142)	33		4
Total current period other comprehensive (loss) income		(2,662)	(397)	(2,549)		(2,526)
Balance		(16,717)	(11,471)	(16,717)		(11,471)
Gain on Sale of Interest Rate Hedge Agreement
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[3]	1,898	2,431	2,164		2,158
Reclassification of stranded tax effects due to adoption of accounting principle	[1],[3]					478
Adjusted beginning balance	[3]							2,636
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications	[3]	0
Amounts reclassified from accumulated other comprehensive (loss) income	[3]	(180)	(180)	(540)		(480)
Effect of taxes	[2],[3]	47	47	141		142
Total current period other comprehensive (loss) income	[3]	(133)	(133)	(399)		(338)
Balance	[3]	1,765	2,298	1,765		2,298
Change in Fair Value of Interest Rate Hedge Agreements
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[4]	(2,964)	1,067	(547)	[5]	441	[5]
Adjusted beginning balance	[4],[5]							441
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications	[4]	(746)	371	(4,083)	[5]	997	[5]
Amounts reclassified from accumulated other comprehensive (loss) income	[4]	90	(41)	144	[5]	(41)	[5]
Effect of taxes	[2],[4]	170	(368)	1,036	[5]	(368)	[5]
Total current period other comprehensive (loss) income	[4]	(486)	(38)	(2,903)	[5]	588	[5]
Balance	[4],[5]	(3,450)	1,029	(3,450)		1,029
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(15,121)	(7,576)	(12,551)		(5,039)
Reclassification of stranded tax effects due to adoption of accounting principle	[1]					(829)
Adjusted beginning balance								$ (5,868)
Current period other comprehensive (loss) income:
Other comprehensive income (loss) before reclassifications		(3,604)	116	(6,665)		(1,533)
Amounts reclassified from accumulated other comprehensive (loss) income		(90)	(221)	(396)		(521)
Effect of taxes	[2]	413	(463)	1,210		(222)
Total current period other comprehensive (loss) income		(3,281)	(568)	(5,851)		(2,276)
Balance		$ (18,402)	$ (8,144)	$ (18,402)		$ (8,144)

[1] The Company has adjusted the balance at December 31, 2017 of accumulated other comprehensive loss for the stranded tax effects caused by the enactment of the Tax Cuts and Jobs Act of 2017 (the “Tax Act”).

[2] The Company’s effective tax rate for the three months ended September 30, 2019 and 2018 was 23.6% and 22.9%, respectively, and 23.2% and 24.0% for the nine months ended September 30, 2019 and 2018, respectively.

[3] 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.

[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 August 31, 2023.

[5] The fair value of the fixed interest rate swaps at September 30, 2019 and December 31, 2018 was $4.7 million and $0.8 million, respectively, and is included in other liabilities on their respective consolidated balance sheet.