Discontinued Operations (Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 0		$ 1,026
Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	0	$ 1,965
Accounts and other receivables, net	55,077	85,399
Inventories	0	855
Other current assets and prepayments	29,801	26,121
Rental property and equipment, net	11,495	12,140
Rental property and equipment, net	0	179
Goodwill	430,995	434,160
Intangible assets	10,379	13,937
Operating lease asset	3,587	4,234
Other assets	27,079	23,833
Assets of discontinued operations	568,413	602,823
Accounts payable and accrued liabilities	38,163	42,896
Current operating lease liabilities	1,441	2,000
Advance billings	98,699	113,110
Other current liabilities	0	2,021
Noncurrent operating lease liabilities	1,823	1,943
Other noncurrent liabilities	16,908	12,828
Liabilities of discontinued operations	$ 157,034	$ 174,798