Reclassifications from Accumulated Other Comprehensive Income - AOCI Roll Forward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ (25,751)		$ (26,768)		$ (25,783)		$ (40,525)
Other comprehensive income (loss) before reclassifications	3,877		(11,189)		2,505		(3,002)
Amounts reclassified from accumulated other comprehensive income	1,255		4,769		2,659		10,339
Net current-period other comprehensive income	5,132		(6,420)		5,164		7,337
Balance at end of period	(20,619)		(33,188)		(20,619)		(33,188)
Net cumulative currency translation gains (losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(201)		264		(469)		(125)
Other comprehensive income (loss) before reclassifications	(1)		(17)		15		372
Amounts reclassified from accumulated other comprehensive income	0		0		252		0
Net current-period other comprehensive income	(1)		(17)		267		372
Balance at end of period	(202)		247		(202)		247
Net unrealized losses on qualifying cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(5,848)		(1,702)		(5,654)		(16,557)
Other comprehensive income (loss) before reclassifications	4,441		(11,187)		3,395		(2,125)
Amounts reclassified from accumulated other comprehensive income	959		4,431		1,811		10,224
Net current-period other comprehensive income	5,400		(6,756)		5,206		8,099
Balance at end of period	(448)		(8,458)		(448)		(8,458)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			0				404
Other comprehensive income (loss) before reclassifications			0				157
Amounts reclassified from accumulated other comprehensive income			0				(561)
Net current-period other comprehensive income			0				(404)
Balance at end of period			0				0
Net unrecognized losses related to pension and severance plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(19,702)	[1]	(25,330)	[1]	(19,660)		(24,247)
Other comprehensive income (loss) before reclassifications	(563)		15		(905)		(1,406)
Amounts reclassified from accumulated other comprehensive income	296		338		596		676
Net current-period other comprehensive income	(267)		353		(309)		(730)
Balance at end of period	(19,969)	[1]	(24,977)	[1]	(19,969)	[1]	(24,977)	[1]
Deferred Tax Liabilities, Other Comprehensive Income	$ 0		$ 0		$ 0		$ 0		$ 271	$ 530	$ 0	$ 0

[1] Net of deferred tax liability of $271, $271, and $530 as of June 30, 2014, March 31, 2014 and December 31, 2013, respectively.