Discontinued Operations (Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 0	$ 1,965	$ 0
DMT | 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	3,241	85,399
Inventories	0	855
Other current assets and prepayments	2,550	26,121
Property, plant and equipment, net	152	12,140
Rental property and equipment, net	0	179
Goodwill	9,562	434,160
Intangible assets, net	0	13,937
Operating lease assets	0	4,234
Other assets	1,724	23,833
Assets of discontinued operations	17,229	602,823
Accounts payable and accrued liabilities	4,340	44,917
Current operating lease liabilities	0	2,000
Advance billings	5,373	113,110
Noncurrent operating lease liabilities	0	1,943
Other noncurrent liabilities	0	12,828
Liabilities of discontinued operations	$ 9,713	174,798
Accumulated impairment charges		$ 148,000