Discontinued Operations and Held For Sale - Summary of Net Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Costs and expenses:
Income from discontinued operations	$ 7,158	$ 373	$ 13,036	$ 494
Income tax expense	(1,422)	(187)	(3,444)	(942)
CBR business | Discontinued Operations, Held-for-sale or Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Service revenues, net	30,085	28,023	59,054	54,955
Costs and expenses:
Cost of services	5,509	5,562	10,983	10,572
Selling, general and administrative expenses	17,531	22,088	35,150	43,889
Total costs and expenses	23,040	27,650	46,133	54,461
Operating income	7,045	373	12,921	494
Other income	113	0	115	0
Income from discontinued operations	7,158	373	13,036	494
Income tax expense	(1,422)	(187)	(3,444)	(942)
Net income (loss) from discontinued operations	$ 5,736	$ 186	$ 9,592	$ (448)