Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 23,229	$ 28	$ 47,056	$ 13,773
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment, net of tax of $6 and $2 for the three and six months ended June 30, 2018, respectively.	(18)	2	(8)	2
Unrealized gain (loss) on available-for-sale securities, net of tax of ($20) and ($29) for the three months ended June 30, 2018 and 2017, respectively, and $77 and ($83) for the six months ended June 30, 2018 and 2017, respectively	57	46	(192)	134
Other comprehensive income (loss)	39	48	(200)	136
Comprehensive income (loss)	23,268	76	46,856	13,909
Comprehensive (income) loss attributable to noncontrolling interests	(159)	(333)	(686)	(1,051)
Comprehensive Income (Loss) Attributable to Stockholders	$ 23,109	$ (257)	$ 46,170	$ 12,858