Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,192	$ 943	$ (2,422)	$ (7,021)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) resulting from changes in fair value of marketable securities	44	3	(39)	(31)
Other comprehensive income (loss), net of tax	44	3	(39)	(31)
Comprehensive income (loss)	5,236	946	(2,461)	(7,052)
Less: Comprehensive (loss) income attributable to noncontrolling interests	(3)	(82)	(9)	1,226
Comprehensive income (loss) attributable to common stockholders	$ 5,239	$ 1,028	$ (2,452)	$ (8,278)