Statement of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 68,644,000	$ 63,084,000	$ 44,985,000
Cash flow hedge adjustments, net of taxes of $224 for the year ended December 31, 2017	(365,000)	0	0
Foreign currency translation adjustment, net of taxes of $56, $185 and ($2,680) for the years ended December 31, 2017, 2016 and 2015, respectively	6,694,000	(514,000)	(11,204,000)
Other adjustments, net of taxes of $0 for the year ended December 31, 2017	(16,000)	0	0
Other Comprehensive Income (Loss), Net of Tax	6,313,000	(514,000)	(11,204,000)
Comprehensive income	74,957,000	62,570,000	33,781,000
Other Comprehensive Income (Loss), Cash Flow Hedge Adjustments, Tax	(224)	0	0
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	56,000	185,000	(2,680,000)
Other Comprehensive (Income) Loss, Other Adjustments, Tax	$ 0	$ 0	$ 0