Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 30,081	$ 25,086
Other comprehensive income, net of tax:
Amortization of loss on cash flow hedge	215	215
Foreign currency translation adjustment	(207)	855
Other comprehensive income, net of tax	8	1,070
Comprehensive income	$ 30,089	$ 26,156

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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