CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (21,799)	$ (6,858)	$ (11,781)
Other comprehensive income (loss), net of taxes:
Interest rate swap settlements	(410)	0	0
Interest rate swap amounts reclassified into interest expense	421	0	0
Unrealized gain resulting from changes in fair value of derivative instruments	155	0	0
Unrealized gain (loss) resulting from changes in fair value of marketable securities	86	(75)	(51)
Other comprehensive income (loss), net of taxes	252	(75)	(51)
Comprehensive loss	(21,547)	(6,933)	(11,832)
Less: Net (loss) income attributable to noncontrolling interests	0	(9)	1,188
Comprehensive loss attributable to common stockholders	$ (21,547)	$ (6,924)	$ (13,020)