Discontinued Operations and Held For Sale - Summary of Cash and Non-cash Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash, cash equivalents and restricted cash at end of period	$ 59,714	$ 62,622
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]
Net cash provided by operating activities	31,642	11,637
Net cash used in investing activities	(1,347)	(1,131)
Net increase in cash, cash equivalents and restricted cash	30,295	10,506
Cash, cash equivalents and restricted cash at beginning of period	29,419	52,116
Cash, cash equivalents and restricted cash at end of period	$ 59,714	$ 62,622