Impairments and Other Charges (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jan. 31, 2020
Tangible Assets And Equipment
Impairment of long-lived assets				$ 147,750
Write offs and charges on long-lived assets	$ 46,295			46,295
Subtotal	46,295			194,045
Goodwill And Intangible Assets:
Goodwill impairments		$ 27,800	$ 93,634	27,798	$ 93,634
Intangible asset impairment			5,235	83,624	5,235
Subtotal			98,869	111,422	98,869
Other Charges:
Provision for international activities	316			15,394
Severance and transaction related costs	11,241			13,425
Loss (gain) on early extinguishment of debt			3,701		1,034
Total impairments and other charges	57,852		$ 102,570	334,286	99,903
Debt Instrument, Repurchased Face Amount	1,300,000			1,300,000		$ 952,900
Payment of long-term debt				1,218,622	361,966
Severance and other related costs				11,200
Drilling And Drilling Solutions
Tangible Assets And Equipment
Impairment of long-lived assets	13,800
Drilling and Rig Services
Tangible Assets And Equipment
Impairment of long-lived assets	$ 32,600
North Slope of Alaska
Tangible Assets And Equipment
Impairment recognized		12,300
U.S. Drilling
Tangible Assets And Equipment
Impairment of long-lived assets		82,400
International Drilling
Tangible Assets And Equipment
Impairment of long-lived assets		30,500
Goodwill And Intangible Assets:
Goodwill impairments					75,600
Drilling Solutions
Tangible Assets And Equipment
Impairment of long-lived assets		19,800
Goodwill And Intangible Assets:
Goodwill impairments				11,436
Rig Technologies
Tangible Assets And Equipment
Impairment of long-lived assets		$ 2,800
Goodwill And Intangible Assets:
Goodwill impairments				$ 16,362	$ 18,000