Discontinued Operations - Summary of Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Costs and expenses:
Income from discontinued operations	$ 0	$ 5,838	$ 0	$ 18,873
Gain on sale of CBR business	0	89,581	0	89,581
Income tax (benefit) expense	0	(98)	0	3,346
Net income from discontinued operations	$ 0	95,517	$ 0	105,108
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		71,217
Costs and expenses:
Cost of services		1,576		12,559
Selling, general and administrative expenses		4,749		39,899
Total costs and expenses		6,325		52,458
Operating income		5,838		18,759
Other income		0		114
Income from discontinued operations		5,838		18,873
Gain on sale of CBR business		89,581		89,581
Income tax (benefit) expense		(98)		3,346
Net income from discontinued operations		$ 95,517		$ 105,108