Assets Held for Sale and Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Discontinued operations
Undiscounted contractual commitments	$ 11,200				$ 17,200				$ 11,200	$ 17,200
Liability related to discontinued operation	8,500				12,500				8,500	12,500
Current liability to discontinued operations	6,074				5,462				6,074	5,462
Operating revenues
Operating revenues									6,169	2,859	$ 3,212
Income (loss) from Oil & Gas discontinued operations:
Income (loss) from Oil and Gas discontinued operations, net of tax	(442)	$ (27,134)	$ (15,504)	$ (439)	(4,266)	$ (12,187)	$ (984)	$ (926)	(43,519)	(18,363)	(42,797)
Litigation expenses and reserves									1,273	3,936	8,194
Sale of business
Other long-term assets	$ 252,854				$ 230,090				252,854	230,090
Assets Held-for-sale
Income (loss) from Oil & Gas discontinued operations:
Impairment charge									35,300	15,400	51,000
Canada | Assets Held-for-sale
Income (loss) from Oil & Gas discontinued operations:
Impairment of note receivable										3,100
Oil and Gas
Income (loss) from Oil & Gas discontinued operations:
Income (loss) from discontinued operations									(2,506)	(3,978)	(5,003)
Less: Impairment charges or other (gains) and losses on sale of wholly owned assets (2)									51,028	19,445	49,890
Less: Income tax expense (benefit)									(10,015)	(5,060)	(14,455)
Income (loss) from Oil and Gas discontinued operations, net of tax									(43,519)	$ (18,363)	(40,438)
Litigation expenses and reserves									$ 16,500
Rig Technologies
Income (loss) from Oil & Gas discontinued operations:
Less: Impairment charges or other (gains) and losses on sale of wholly owned assets (2)											3,146
Less: Income tax expense (benefit)											(787)
Income (loss) from Oil and Gas discontinued operations, net of tax											$ (2,359)