Discontinued Operations and Held For Sale - Summary of Net Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Costs and expenses:
Income from discontinued operations	$ 5,838	$ 4,506	$ 18,873	$ 4,998
Gain on sale of CBR business	89,581	0	89,581	0
Income tax (benefit) expense	(98)	854	3,346	1,796
Net income from discontinued operations	95,517	3,652	105,108	3,202
CBR business
Costs and expenses:
Gain on sale of CBR business	89,600		89,600
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	12,163	29,410	71,217	84,365
Costs and expenses:
Cost of services	1,576	5,559	12,559	16,130
Selling, general and administrative expenses	4,749	19,345	39,899	63,237
Total costs and expenses	6,325	24,904	52,458	79,367
Operating income	5,838	4,506	18,759	4,998
Other income	0	0	114	0
Income from discontinued operations	5,838	4,506	18,873	4,998
Gain on sale of CBR business	89,581	0	89,581	0
Income tax (benefit) expense	(98)	854	3,346	1,796
Net income from discontinued operations	$ 95,517	$ 3,652	$ 105,108	$ 3,202