Discontinued Operations (Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 1,026		$ 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	1,026	$ 0
Accounts receivable, net	2,900	97,402
Inventories	4,360	48,910
Other current assets and prepayments	188	3,365
Property, plant and equipment, net	578	5,541
Rental property and equipment, net	386	1,786
Goodwill	8,787	177,799
Other assets	48	45
Assets of discontinued operations	18,273	334,848
Accounts payable and accrued liabilities	2,261	36,592
Advance billings	2,534	30,607
Other noncurrent liabilities	5,651	5,609
Liabilities of discontinued operations	$ 10,446	$ 72,808