CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Thousands, $ in Thousands	Mandatory Convertible Preferred Shares Preferred Stock	Common Stock	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, 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)
Other comprehensive income (loss), net of tax				12,758			55	12,813
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options			(79)					(79)
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options (in shares)	(4)
Share-based compensation			19,489					19,489
Noncontrolling interest contributions (distributions)							(4,551)	(4,551)
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)
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
Balance at the beginning of the period at Dec. 31, 2019	$ 6	$ 416	3,412,972	(11,788)	(104,775)	(1,314,020)	67,354	2,050,165
Balance (in shares) at Dec. 31, 2019	5,613	416,198
Increase (Decrease) in Equity
Net income (loss)					(697,404)		38,437	(658,967)
Dividends to common shareholders					(3,633)			(3,633)
Dividends to preferred shareholders					(10,958)			(10,958)
Repurchase of preferred shares	$ (1)		(12,126)			(1,731)		(13,858)
Repurchase of preferred shares (in shares)	(743)
Other comprehensive income (loss), net of tax				(6,842)				(6,842)
Share-based compensation			20,170					20,170
Noncontrolling interest contributions (distributions)							(2,032)	(2,032)
Accrued distribution on redeemable noncontrolling interest in subsidiary					(13,092)			(13,092)
Other		$ 3	(1,549)				357	(1,189)
Other (in shares)		(407,813)
Balance at the end of the period at Sep. 30, 2020	$ 5	$ 419	3,419,467	(18,630)	(829,862)	(1,315,751)	104,116	1,359,764
Balance (in shares) at Sep. 30, 2020	4,870	8,385
Balance at the beginning of the period at Jun. 30, 2020	$ 5	$ 419	3,415,053	(22,188)	(664,391)	(1,315,751)	94,339	1,507,486
Balance (in shares) at Jun. 30, 2020	4,870	8,389
Increase (Decrease) in Equity
Net income (loss)					(157,465)		10,805	(146,660)
Dividends to preferred shareholders					(3,653)			(3,653)
Other comprehensive income (loss), net of tax				3,558				3,558
Accrued distribution on redeemable noncontrolling interest in subsidiary					(4,353)			(4,353)
Other			4,414				(1,028)	3,386
Other (in shares)		(4)
Balance at the end of the period at Sep. 30, 2020	$ 5	$ 419	$ 3,419,467	$ (18,630)	$ (829,862)	$ (1,315,751)	$ 104,116	$ 1,359,764
Balance (in shares) at Sep. 30, 2020	4,870	8,385