CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ in Thousands	Mandatory Convertible Preferred Shares Preferred Stock	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, 2017		$ 368	$ 2,791,129	$ 11,185	$ 1,423,154	$ (1,314,020)	$ 26,957	$ 2,938,773
Balance (in shares) at Dec. 31, 2017		367,510
Increase (Decrease) in Equity
Net income (loss)					(457,530)		10,426	(447,104)
Dividends to common shareholders					(61,956)			(61,956)
Dividends to preferred shareholders					(7,993)			(7,993)
Common share issuance		$ 40	301,794					301,834
Common share issuance (in shares)		40,250
Convertible preferred share issuance	$ 6		278,352					278,358
Convertible preferred share issuance (in shares)	5,750
Other comprehensive income (loss), net of tax				(18,300)			(101)	(18,401)
Share-based compensation			20,371					20,371
Adjustment to retained earnings | Accounting Standards Update 2016-01					9,144			9,144
Adjustment to retained earnings | Accounting Standards Update 2016-16					(34,132)			(34,132)
Adjustment to retained earnings				(9,144)
Noncontrolling interest contributions (distributions)							(4,676)	(4,676)
Less: accrued distribution on redeemable noncontrolling interest in subsidiary					(6,668)			(6,668)
Other		$ 2	(3,724)					(3,722)
Other (in shares)		2,400
Balance at the end of the period at Sep. 30, 2018	$ 6	$ 410	3,387,922	(7,115)	864,019	(1,314,020)	32,606	2,963,828
Balance (in shares) at Sep. 30, 2018	5,750	410,160
Balance at the beginning of the period at Jun. 30, 2018	$ 6	$ 410	3,382,711	(12,573)	1,006,500	(1,314,020)	25,614	3,088,648
Balance (in shares) at Jun. 30, 2018	5,750	410,252
Increase (Decrease) in Equity
Net income (loss)					(114,577)		6,934	(107,643)
Dividends to common shareholders					(21,445)			(21,445)
Dividends to preferred shareholders					(4,313)			(4,313)
Common share issuance			(180)					(180)
Convertible preferred share issuance			(214)					(214)
Other comprehensive income (loss), net of tax				5,458			58	5,516
Share-based compensation			5,639					5,639
Less: accrued distribution on redeemable noncontrolling interest in subsidiary					(2,146)			(2,146)
Other			(34)					(34)
Other (in shares)		(92)
Balance at the end of the period at Sep. 30, 2018	$ 6	$ 410	3,387,922	(7,115)	864,019	(1,314,020)	32,606	2,963,828
Balance (in shares) at Sep. 30, 2018	5,750	410,160
Balance at the beginning of the period at Dec. 31, 2018	$ 6	$ 410	3,392,937	(29,325)	650,842	(1,314,020)	49,476	2,750,326
Balance (in shares) at Dec. 31, 2018	5,750	409,652
Increase (Decrease) in Equity
Net income (loss)					(440,201)		44,202	(395,999)
Dividends to common shareholders					(11,209)			(11,209)
Dividends to preferred shareholders					(12,935)			(12,935)
Repurchase of preferred shares			(79)					(79)
Repurchase of preferred shares (in shares)	(4)
Other comprehensive income (loss), net of tax				12,758			55	12,813
Share-based compensation			19,489					19,489
Adjustment to retained earnings								0
Noncontrolling interest contributions (distributions)							(4,551)	(4,551)
Less: accrued distribution on redeemable noncontrolling interest in subsidiary					(15,358)			(15,358)
Other		$ 6	(1,616)					(1,610)
Other (in shares)		6,557
Balance at the end of the period at Sep. 30, 2019	$ 6	$ 416	3,410,731	(16,567)	171,139	(1,314,020)	89,182	2,340,887
Balance (in shares) at Sep. 30, 2019	5,746	416,209
Balance at the beginning of the period at Jun. 30, 2019	$ 6	$ 416	3,405,421	(13,490)	303,181	(1,314,020)	73,627	2,455,141
Balance (in shares) at Jun. 30, 2019	5,746	416,282
Increase (Decrease) in Equity
Net income (loss)					(118,928)		19,297	(99,631)
Dividends to common shareholders					(3,628)			(3,628)
Dividends to preferred shareholders					(4,310)			(4,310)
Other comprehensive income (loss), net of tax				(3,077)			(4)	(3,081)
Share-based compensation			5,325					5,325
Noncontrolling interest contributions (distributions)							(3,738)	(3,738)
Less: accrued distribution on redeemable noncontrolling interest in subsidiary					(5,176)			(5,176)
Other			(15)					(15)
Other (in shares)		(73)
Balance at the end of the period at Sep. 30, 2019	$ 6	$ 416	$ 3,410,731	$ (16,567)	$ 171,139	$ (1,314,020)	$ 89,182	$ 2,340,887
Balance (in shares) at Sep. 30, 2019	5,746	416,209