CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	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, 2014	$ 328	$ 2,452,261	$ 77,522	$ 3,573,172	$ (1,194,664)	$ 10,170	$ 4,918,789
Balance (in shares) at Dec. 31, 2014	328,196
Increase (Decrease) in Equity
Net income (loss)				86,813		(133)	86,680
Dividends to shareholders				(34,980)			(34,980)
Other comprehensive income (loss), net of tax			(52,366)			(718)	(53,084)
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options		1,198					1,198
Issuance of common shares for stock options exercised (in shares)	130
Share-based compensation		30,102					30,102
Other	$ 3	(7,429)				(1,904)	(9,330)
Other (in shares)	2,317
Balance at the end of the period at Jun. 30, 2015	$ 331	2,476,132	25,156	3,625,005	(1,194,664)	7,415	4,939,375
Balance (in shares) at Jun. 30, 2015	330,643
Balance at the beginning of the period at Dec. 31, 2015	$ 331	2,493,100	(47,593)	3,131,134	(1,294,262)	11,158	4,293,868
Balance (in shares) at Dec. 31, 2015	330,526
Increase (Decrease) in Equity
Net income (loss)				(582,944)		(2,175)	(585,119)
Dividends to shareholders				(33,925)			(33,925)
Repurchase of treasury shares					(1,687)		(1,687)
Other comprehensive income (loss), net of tax			39,343			461	39,804
Issuance of common shares for stock options exercised, net of surrender of unexercised stock options		39					39
Issuance of common shares for stock options exercised (in shares)	4
Share-based compensation		16,596					16,596
Other	$ 2	(4,284)				(2,596)	(6,878)
Other (in shares)	2,524
Balance at the end of the period at Jun. 30, 2016	$ 333	$ 2,505,451	$ (8,250)	$ 2,514,265	$ (1,295,949)	$ 6,848	$ 3,722,698
Balance (in shares) at Jun. 30, 2016	333,054