Discontinued Operations - Summary of Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Costs and expenses:
Income from discontinued operations	$ 0	$ 7,158	$ 0	$ 13,036
Income tax expense	0	1,422	0	3,444
Net income from discontinued operations	$ 0	5,736	$ 0	9,592
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		59,054
Costs and expenses:
Cost of services		5,509		10,983
Selling, general and administrative expenses		17,531		35,150
Total costs and expenses		23,040		46,133
Operating income		7,045		12,921
Other income		113		115
Income from discontinued operations		7,158		13,036
Income tax expense		1,422		3,444
Net income from discontinued operations		$ 5,736		$ 9,592