Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 13,745	$ 11,870
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of tax of ($61) for the three months ended March 31, 2016	0	99
Unrealized gain on available-for-sale securities, net of tax of $(54) and ($97) for the three months ended March 31, 2017 and 2016, respectively	88	160
Other comprehensive income	88	259
Comprehensive income	13,833	12,129
Comprehensive (income) loss attributable to noncontrolling interests	(718)	493
Comprehensive Income Attributable to Stockholders	$ 13,115	$ 12,622