Restatement of Previously Issued Financial Statements Restatement of Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended							6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net earnings (loss)	$ (730,653)	$ (452,699)	$ (45,045)	$ 67,088	$ 97,868	$ 88,654	$ (20,756)	$ (497,744)	$ 67,899	$ (1,228,397)	$ 165,767	$ (1,553,124)	$ 232,853	$ 226,764
Loss on pension settlement	0	0	0	1,366	18,641	1,893	0					137,900	21,900	184
Write-off of cumulative translation loss												83,665	0	0
Depreciation			45,264				51,907	87,871	102,503	129,014	150,592	154,599	197,585	206,113
Amortization of intangibles			4,567				4,747	9,043	9,403	13,032	14,327	15,882	19,071	19,156
(Earnings) loss from equity method investments, net of distributions			2,115				1,854	7,891	1,919	6,510	506	9,348	980	2,849
Gain on sale of joint venture interest												0	(124,942)	0
(Gain) loss on sales of property, plant and equipment			(1,858)				(2,153)	(3,552)	(7,347)	5,690	(124,942)	7,284	(22,132)	(22,746)
Loss on impairment								39,115	0	347,411	(15,595)	383,017	0	0
Amortization of stock-based awards			13,242				13,917	29,803	23,990	27,513	34,735	36,075	43,029	40,669
Deferred compensation trust			(26,145)				1,025	(34,412)	(2,826)	(36,989)	(14,915)	(55,820)	18,010	(49,539)
Deferred compensation obligation			28,584				930	36,593	3,145	34,827	19,320	54,490	(22,272)	52,615
Deferred taxes			(21,174)				(40,517)	(127,664)	3,548	316,407	17,556	320,633	60,709	100,144
Net retirement plan accrual (contributions)			(3,577)				(5,235)	(1,827)	(3,056)	(1,821)	(16,552)	(2,325)	(38,372)	(9,030)
Changes in assets and liabilities			(16,566)				(139,759)	541,541	(331,087)	443,662	(242,693)	633,029	(227,732)	25,948
Other			3,117				(1,962)	4,777	(691)	10,039	609	(5,633)	3,477	8,844
Operating cash flow			(17,476)				(136,002)	91,435	(132,600)	66,898	(11,285)	$ 219,018	162,164	601,971
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net earnings (loss)	(729,539)	(593,486)	(43,308)	77,831	96,025	131,163	(12,061)	(636,794)	119,103	(1,366,333)	215,128		292,958	264,469
Loss on pension settlement	0	0	0	1,366	18,641	1,893	0						21,900	184
Write-off of cumulative translation loss													0	0
Depreciation			45,264				51,907	87,871	102,503	129,014	150,592		197,585	206,113
Amortization of intangibles			4,567				4,747	9,043	9,403	13,032	14,327		19,071	19,156
(Earnings) loss from equity method investments, net of distributions			2,115				1,854	7,891	1,919	6,510	506		980	2,849
Gain on sale of joint venture interest													(124,942)	0
(Gain) loss on sales of property, plant and equipment			(1,858)				(2,153)	(3,552)	(7,347)	5,690	(124,942)		(22,132)	(22,746)
Loss on impairment								39,115	0	347,411	(15,595)		0	0
Amortization of stock-based awards			13,242				13,917	29,803	23,990	27,513	34,735		43,029	40,669
Deferred compensation trust			(26,145)				1,025	(34,412)	(2,826)	(36,989)	(14,915)		18,010	(49,539)
Deferred compensation obligation			28,584				930	36,593	3,145	34,827	19,320		(22,272)	52,615
Deferred taxes			(25,549)				(37,920)	(173,488)	15,619	270,996	30,969		70,594	100,286
Net retirement plan accrual (contributions)			(3,577)				(5,235)	(1,827)	(3,056)	(1,821)	(16,552)		(38,372)	(9,030)
Changes in assets and liabilities			(13,928)				(151,051)	726,415	(394,362)	627,009	(305,467)		(297,722)	(11,899)
Other			3,117				(1,962)	4,777	(691)	10,039	609		3,477	8,844
Operating cash flow			(17,476)				(136,002)	91,435	(132,600)	66,898	(11,285)		162,164	601,971
Radford Adjustments | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net earnings (loss)	(705)	134,833	(3,336)	(17,845)	(8,820)	(7,468)	(8,695)	131,497	(16,163)	130,792	(24,983)		(42,828)	(38,413)
Loss on pension settlement	0	$ 0	0	0	0	0	0						0	0
Write-off of cumulative translation loss													0	0
Depreciation			0				0	0	0	0	0		0	0
Amortization of intangibles			0				0	0	0	0	0		0	0
(Earnings) loss from equity method investments, net of distributions			0				0	0	0	0	0		0	0
Gain on sale of joint venture interest													0	0
(Gain) loss on sales of property, plant and equipment			0				0	0	0	0	0		0	0
Loss on impairment								0	0	0	0		0	0
Amortization of stock-based awards			0				0	0	0	0	0		0	0
Deferred compensation trust			0				0	0	0	0	0		0	0
Deferred compensation obligation			0				0	0	0	0	0		0	0
Deferred taxes			(997)				(2,597)	39,278	(4,828)	39,068	(7,461)		(12,793)	1,107
Net retirement plan accrual (contributions)			0				0	0	0	0	0		0
Changes in assets and liabilities			4,333				11,292	(170,775)	20,991	(169,860)	32,444		55,621	37,306
Other			0					0	0	0	0		0	0
Operating cash flow			0				$ 0	0	0	0	0		0	0
Infrastructure Adjustments | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net earnings (loss)			12,808	(12,808)	10,079	(10,079)		12,808	(10,079)	12,808			(12,808)
Loss on pension settlement			0	0	$ 0	0							0
Write-off of cumulative translation loss													0
Depreciation			0					0	0	0			0
Amortization of intangibles			0					0	0	0			0
(Earnings) loss from equity method investments, net of distributions			0					0	0	0			0
Gain on sale of joint venture interest													0
(Gain) loss on sales of property, plant and equipment			0					0	0	0			0
Loss on impairment								0	0	0			0
Amortization of stock-based awards			0					0	0	0			0
Deferred compensation trust			0					0	0	0			0
Deferred compensation obligation			0					0	0	0			0
Deferred taxes			1,291					1,291	(1,249)	1,291			(1,291)
Net retirement plan accrual (contributions)			0					0	0	0			0
Changes in assets and liabilities			(14,099)					(14,099)	11,328	(14,099)			14,099
Other			0					0	0	0			0
Operating cash flow			0					0	0	0			0
Other Adjustments | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net earnings (loss)	(409)		(5,255)	3,435		(7,903)		(5,255)	(7,903)	(5,664)	(7,903)		(4,469)	708
Loss on pension settlement	$ 0		0	$ 0		$ 0							0	0
Write-off of cumulative translation loss													0	0
Depreciation			0					0	0	0	0		0	0
Amortization of intangibles			0					0	0	0	0		0	0
(Earnings) loss from equity method investments, net of distributions			0					0	0	0	0		0	0
Gain on sale of joint venture interest													0	0
(Gain) loss on sales of property, plant and equipment			0					0	0	0	0		0	0
Loss on impairment								0	0	0	0		0	0
Amortization of stock-based awards			0					0	0	0	0		0	0
Deferred compensation trust			0					0	0	0	0		0	0
Deferred compensation obligation			0					0	0	0	0		0	0
Deferred taxes			5,311					5,255	(2,461)	5,052	(2,490)		4,199	(1,249)
Net retirement plan accrual (contributions)			0					0	0	0	0		0
Changes in assets and liabilities			(56)					0	10,364	612	10,393		270	541
Other			0					0	0	0	0		0	0
Operating cash flow			$ 0					$ 0	$ 0	$ 0	$ 0		$ 0	$ 0