Dispositions - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Sep. 30, 2017	Dec. 31, 2018	Sep. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 27, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reclassification of foreign currency translation loss to investment, net of tax				$ 0	$ 0	$ 31,381
Chevron | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposal		$ 152,800
NexTraq | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration							$ 316,500
Gain on disposal			$ 175,000
Tax effect of gain from disposal			$ 65,800
Masternaut
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment loss on investment	$ 44,600			15,600
Cumulative impairment loss on investments				$ 136,300
Reclassification of foreign currency translation loss to investment, net of tax						$ 31,400