Segment Information - By Geographic Area (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) customer	Dec. 31, 2017 USD ($) customer	Dec. 31, 2016 USD ($) customer
Financial information with respect to entity's operations by geographic area
Operating revenues	$ 782,080,000	$ 779,425,000	$ 761,920,000	$ 734,194,000	$ 708,277,000	$ 662,103,000	$ 631,355,000	$ 562,550,000	$ 3,057,619,000	$ 2,564,285,000	$ 2,227,839,000
Property, Plant and Equipment, Net	5,467,870,000				6,109,565,000				5,467,870,000	6,109,565,000	6,267,583,000
Goodwill	183,914,000				173,226,000				$ 183,914,000	$ 173,226,000	$ 166,917,000
Sales Revenue | One customer
Financial information with respect to entity's operations by geographic area
Number of customers | customer									1	1	1
Sales Revenue | Customer Concentration Risk | One customer
Financial information with respect to entity's operations by geographic area
Percentage									24.00%	29.00%	33.00%
U.S. Drilling
Financial information with respect to entity's operations by geographic area
Operating revenues									$ 1,347,448,000	$ 973,464,000	$ 642,835,000
Property, Plant and Equipment, Net	2,892,910,000				3,163,425,000				2,892,910,000	3,163,425,000	3,048,749,000
Goodwill	65,633,000				54,198,000				65,633,000	54,198,000	54,199,000
Outside the U.S
Financial information with respect to entity's operations by geographic area
Operating revenues									1,710,171,000	1,590,821,000	1,585,004,000
Property, Plant and Equipment, Net	2,574,960,000				2,946,140,000				2,574,960,000	2,946,140,000	3,218,834,000
Goodwill	$ 118,281,000				$ 119,028,000				118,281,000	119,028,000	112,718,000
Saudi Arabia
Financial information with respect to entity's operations by geographic area
Operating revenues									$ 764,500,000	$ 727,700,000	$ 731,400,000