Summary of Significant Accounting Policies - Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Change in the carrying amount of goodwill for various contract drilling segments and other operating segments
Goodwill - Beginning Balance	$ 173,226,000	$ 166,917,000
Acquisitions and purchase price adjustment	11,436,000	5,690,000
Cumulative Translation Adjustment	(748,000)	619,000
Goodwill - Ending Balance	$ 183,914,000	173,226,000
Goodwill
Long-term growth rate used to calculate terminal values for each reporting unit (as a percent)	3.00%
Discontinued Operation, additional disclosures
Goodwill for the consolidated company, expected to be deductible for tax purposes	$ 9,200,000
U.S. Drilling
Change in the carrying amount of goodwill for various contract drilling segments and other operating segments
Goodwill - Beginning Balance	50,149,000	50,149,000
Goodwill - Ending Balance	50,149,000	50,149,000
International Drilling
Change in the carrying amount of goodwill for various contract drilling segments and other operating segments
Goodwill - Beginning Balance	75,634,000	75,634,000
Goodwill - Ending Balance	75,634,000	75,634,000
Drilling Solutions
Change in the carrying amount of goodwill for various contract drilling segments and other operating segments
Acquisitions and purchase price adjustment	11,436,000
Goodwill - Ending Balance	11,436,000
Rig Technologies
Change in the carrying amount of goodwill for various contract drilling segments and other operating segments
Goodwill - Beginning Balance	47,443,000	41,134,000
Acquisitions and purchase price adjustment		5,690,000
Cumulative Translation Adjustment	(748,000)	619,000
Goodwill - Ending Balance	$ 46,695,000	$ 47,443,000