CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Comprehensive Income (Loss)
Net Income	$ 58,499	$ 56,567
Other comprehensive income, net of tax:
Foreign currency translation	95	51
Reclassification of net losses on derivative instruments	113	93
Total Other Comprehensive Income	208	144
Comprehensive Income	$ 58,707	$ 56,711