CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 7,537	$ 2,259	$ 5,116	$ (4,762)
Other comprehensive income (loss), net of tax:
Unrealized loss resulting from changes in fair value of marketable securities	(10)	(44)	(50)	(75)
Other comprehensive loss, net of tax	(10)	(44)	(50)	(75)
Comprehensive income (loss)	7,527	2,215	5,066	(4,837)
Less: Comprehensive income (loss) attributable to noncontrolling interests	0	(37)	(9)	1,189
Comprehensive income (loss) attributable to common stockholders	$ 7,527	$ 2,252	$ 5,075	$ (6,026)