CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenue from services	$ 865,048	$ 833,537	$ 767,421
Operating expenses:
Direct operating expenses	636,462	611,802	570,056
Selling, general, and administrative expenses	187,435	179,820	161,275
Bad debt expense	1,828	593	999
Depreciation and amortization	10,174	9,182	8,066
Loss on sale of business	0	0	2,184
Acquisition-related contingent consideration	44	814	0
Acquisition and integration costs	1,975	78	902
Restructuring costs	1,026	753	1,274
Impairment charges	14,356	24,311	2,100
Total operating expenses	853,300	827,353	746,856
Income from operations	11,748	6,184	20,565
Other expenses (income):
Interest expense	4,214	6,106	6,810
(Gain) loss on derivative liability	(1,581)	(5,805)	9,901
Loss on early extinguishment of debt	4,969	1,568	0
Other income, net	(155)	(230)	(306)
Income before income taxes	4,301	4,545	4,160
Income tax benefit	(34,501)	(4,186)	(794)
Consolidated net income	38,802	8,731	4,954
Less: Net income attributable to noncontrolling interest in subsidiary	1,289	764	536
Net income attributable to common shareholders	$ 37,513	$ 7,967	$ 4,418
Net income per share attributable to common shareholders - Basic (usd per share)	$ 1.07	$ 0.25	$ 0.14
Net income per share attributable to common shareholders - Diluted (usd per share)	$ 1.01	$ 0.15	$ 0.14
Weighted average common shares outstanding—basic (shares)	35,018	32,132	31,514
Weighted average common shares outstanding—diluted (shares)	36,166	36,246	32,162