Divestments - Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		$ 4,009		$ 4,009
Income (Loss) from Discontinued Operations Before Provision (Benefit) for Income Taxes	$ (3,049)	1,876	$ (3,478)	1,876
Provision (Benefit) for Income Taxes	(1,023)	289	(1,115)	289
Income (Loss) from Discontinued Operations, Net of Tax	(2,026)	1,587	(2,363)	1,587
Initial United States Divestments | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		0		0
Income (Loss) from Discontinued Operations Before Provision (Benefit) for Income Taxes	0	0	0	0
Provision (Benefit) for Income Taxes	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax	0	0	0	0
Seattle/Atlanta Divestments | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		1,810		1,810
Income (Loss) from Discontinued Operations Before Provision (Benefit) for Income Taxes	(1,801)	934	(1,562)	934
Provision (Benefit) for Income Taxes	(646)	44	(605)	44
Income (Loss) from Discontinued Operations, Net of Tax	(1,155)	890	(957)	890
Recall Canadian Divestments | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		1,888		1,888
Income (Loss) from Discontinued Operations Before Provision (Benefit) for Income Taxes	(1,248)	867	(1,916)	867
Provision (Benefit) for Income Taxes	(377)	232	(510)	232
Income (Loss) from Discontinued Operations, Net of Tax	(871)	635	(1,406)	635
UK Divestments | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Revenue		311		311
Income (Loss) from Discontinued Operations Before Provision (Benefit) for Income Taxes	0	75	0	75
Provision (Benefit) for Income Taxes	0	13	0	13
Income (Loss) from Discontinued Operations, Net of Tax	$ 0	$ 62	$ 0	$ 62