CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($)	Mandatory Convertible Preferred Shares	Common Shares	Capital in Excess of Par Value	Accumulated Other Comprehensive Income	Retained Earnings	Treasury Shares	Non-controlling Interest	Total
Balance at the beginning of the period at Dec. 31, 2015		$ 331,000	$ 2,493,100,000	$ (47,593,000)	$ 3,131,134,000	$ (1,294,262,000)	$ 11,158,000	$ 4,293,868,000
Balance (in shares) at Dec. 31, 2015		330,526
Increase (Decrease) in Equity
Net income (loss)					(1,029,742,000)		135,000	(1,029,607,000)
Dividends to common shareholders ($0.24 per share)					(67,965,000)			(67,965,000)
Repurchase of treasury shares						(1,687,000)		(1,687,000)
Repurchase of common stock								1,687,000
Other comprehensive income (loss), net of tax				35,474,000			251,000	35,725,000
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options			967,000					967,000
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options (in shares)		102
Share-based compensation			32,000,000					32,000,000
Other		$ 3,000	(4,735,000)				(3,774,000)	(8,506,000)
Other (in shares)		2,970
Balance at the end of the period at Dec. 31, 2016		$ 334,000	2,521,332,000	(12,119,000)	2,033,427,000	(1,295,949,000)	7,770,000	3,254,795,000
Balance (in shares) at Dec. 31, 2016		333,598
Increase (Decrease) in Equity
Net income (loss)					(546,811,000)		6,178,000	(540,633,000)
Dividends to common shareholders ($0.24 per share)					(68,612,000)			(68,612,000)
Repurchase of treasury shares						(18,071,000)		(18,071,000)
Repurchase of common stock								$ 18,071,000
Repurchase of common stock (in shares)								3,100,000
Other comprehensive income (loss), net of tax				23,304,000			282,000	$ 23,586,000
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options		$ 1,000	(10,736,000)					(10,735,000)
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options (in shares)		842
Equity component of exchangeable debt			116,195,000					116,195,000
Capped call transactions			(40,250,000)					(40,250,000)
Adoption of ASU No. 2016-09			1,943,000		5,150,000			7,093,000
Share-based compensation			31,896,000					31,896,000
Issuance to Tesco shareholders		$ 32,000	178,961,000					178,993,000
Issuance to Tesco shareholders (in shares)		32,078
Noncontrolling interest contributions (distributions), net							13,018,000	13,018,000
Other		$ 1,000	(8,212,000)				(291,000)	(8,502,000)
Other (in shares)		992
Balance at the end of the period at Dec. 31, 2017		$ 368,000	2,791,129,000	11,185,000	1,423,154,000	(1,314,020,000)	26,957,000	2,938,773,000
Balance (in shares) at Dec. 31, 2017		367,510
Increase (Decrease) in Equity
Net income (loss)					(640,948,000)		28,222,000	(612,726,000)
Dividends to common shareholders ($0.24 per share)					(82,973,000)			(82,973,000)
Dividends to preferred shareholders ($2.14 per share)					(12,305,000)			(12,305,000)
Common share issuance		$ 40,000	301,363,000					301,403,000
Common share issuance (in shares)		40,250
Convertible preferred stock issuance	$ 6,000		277,921,000					277,927,000
Convertible preferred stock issuance (in shares)	5,750
Other comprehensive income (loss), net of tax				(40,510,000)			(251,000)	(40,761,000)
Share-based compensation			26,396,000					26,396,000
Adjustment to retained earnings | Accounting Standards Update 2016-01					9,144,000
Adjustment to retained earnings | Accounting Standards Update 2016-16					(34,132,000)
Adjustment to retained earnings				9,144,000
Noncontrolling interest contributions (distributions), net							(5,452,000)	(5,452,000)
Less: accrued distribution on redeemable noncontrolling interest in subsidiary					(11,098,000)			(11,098,000)
Other		$ 2,000	(3,872,000)					(3,870,000)
Other (in shares)		1,892
Balance at the end of the period at Dec. 31, 2018	$ 6	$ 410,000	$ 3,392,937,000	$ (29,325,000)	$ 650,842,000	$ (1,314,020,000)	$ 49,476,000	$ 2,750,326,000
Balance (in shares) at Dec. 31, 2018	5,750	409,652