Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income (loss)	$ 17,836	$ 31,100	$ (6,767)	$ 33,477
Other comprehensive income (loss), net of tax, where applicable: [Abstract]
Unrealized foreign currency translation gains (losses)	(1)	(17)	15	372
Realized gains for foreign currency translation on business disposal reclassified into Other income (expense), net	0	0	252	0
Net other comprehensive income (loss) related to foreign currency translation	(1)	(17)	267	372
Change in fair value of available-for-sale investment	0	0	0	157
Realized gains of available-for-sale investment reclassified into Other income (expense), net	0	0	0	(561)
Net other comprehensive loss related to available-for-sale investment	0	0	0	(404)
Unrealized gains (losses) on derivatives for the period	4,441	(11,187)	3,395	(2,125)
Derivative losses reclassified into Net sales	1,020	6,582	2,047	15,214
Derivative gains reclassified into Cost of sales	(61)	(2,151)	(236)	(4,990)
Net other comprehensive income (loss) related to derivatives	5,400	(6,756)	5,206	8,099
Actuarial gains (losses) for the period, net of $0, $15, $(259) and $(130), respectively, of income tax expense (benefit)	(563)	15	(905)	(1,406)
Amortization included in pension cost	296	338	596	676
Net other comprehensive gain (loss) related to defined benefit pension and severance plans	(267)	353	(309)	(730)
Other comprehensive income (loss), net of tax	5,132	(6,420)	5,164	7,337
Comprehensive income (loss)	$ 22,968	$ 24,680	$ (1,603)	$ 40,814