Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 23,827	$ 13,745
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment, net of tax of ($4) for the three months ended March 31, 2018	10	0
Unrealized gain (loss) on available-for-sale securities, net of tax of $97 and $(54) for the three months ended March 31, 2018 and 2017, respectively	(249)	88
Other comprehensive income (loss)	(239)	88
Comprehensive income (loss)	23,588	13,833
Comprehensive (income) loss attributable to noncontrolling interests	(527)	(718)
Comprehensive Income (Loss) Attributable to Stockholders	$ 23,061	$ 13,115