Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		$ 616,030	$ 566,004	$ 523,276
Current period other comprehensive income (loss):
Total current period other comprehensive (loss) income		(6,683)	4,601	(2,149)
Balance		660,417	616,030	566,004
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(7,638)	(11,815)	(7,491)
Reclassification of stranded tax effects due to adoption of accounting principle	[1]	(1,307)
Adjusted beginning balance		(8,945)
Current period other comprehensive income (loss):
Other comprehensive (loss) income before reclassifications		(4,711)	6,476	(7,924)
Effect of taxes	[2]	(512)	(2,299)	3,600
Total current period other comprehensive (loss) income		(5,223)	4,177	(4,324)
Balance		(14,168)	(7,638)	(11,815)
Adjusted beginning balance		(8,945)
Gain on Sale of Interest Rate Hedge Agreement
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[3]	2,158	2,175
Reclassification of stranded tax effects due to adoption of accounting principle	[1],[3]	478
Adjusted beginning balance	[3]	2,636
Current period other comprehensive income (loss):
Other comprehensive (loss) income before reclassifications	[3]			3,600
Amounts reclassified from accumulated other comprehensive income	[3]	(660)
Effect of taxes	[2],[3]	188	(17)	(1,425)
Total current period other comprehensive (loss) income	[3]	(472)	(17)	2,175
Balance	[3]	2,164	2,158	2,175
Adjusted beginning balance	[3]	2,636
Change in Fair Value of Interest Rate Hedge Agreements
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	[4],[5]	441
Adjusted beginning balance	[4],[5]	441
Current period other comprehensive income (loss):
Other comprehensive (loss) income before reclassifications	[4],[5]	(1,184)	441
Amounts reclassified from accumulated other comprehensive income	[4],[5]	(12)
Effect of taxes	[2],[4],[5]	208
Total current period other comprehensive (loss) income	[4],[5]	(988)	441
Balance	[4],[5]	(547)	441
Adjusted beginning balance	[4],[5]	441
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Balance		(5,039)	(9,640)	(7,491)
Reclassification of stranded tax effects due to adoption of accounting principle	[1]	(829)
Adjusted beginning balance		(5,868)
Current period other comprehensive income (loss):
Other comprehensive (loss) income before reclassifications		(5,895)	6,917	(4,324)
Amounts reclassified from accumulated other comprehensive income		(672)
Effect of taxes	[2]	(116)	(2,316)	2,175
Total current period other comprehensive (loss) income		(6,683)	4,601	(2,149)
Balance		(12,551)	$ (5,039)	$ (9,640)
Adjusted beginning balance		$ (5,868)

[1] The Company has adjusted the balance of accumulated other comprehensive (loss) income at December 31, 2017 after the adoption of ASU 2018-02. See additional details of the adoption of ASU 2018-02 in Note 2 – Summary of Significant Accounting Policies.

[2] The Company’s effective tax rate for the years ended December 31, 2018, 2017, and 2016 was 25.9%, 15.0%, and 37.5%, respectively.

[3] Represents the fair 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 was recorded in other comprehensive income, net of tax, and will be reclassified to earnings when earnings are impacted by the hedged items, 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 an interest rate hedge agreement designated as a cash flow hedge and entered into on August 31, 2017. The fair value of the interest rate hedge agreement was recorded in other comprehensive income and will be reclassified to earnings when earnings are impacted by the hedged items, as interest payments are made on the Credit Facility from August 31, 2018 to August 31, 2023. See additional details of the hedge agreement in Note 10 - Derivative Instruments and Hedging Activities.

[5] The fair value of the interest rate hedge agreements is included in other liabilities on the consolidated balance sheet.