Reclassifications from Accumulated Other Comprehensive Income - AOCI Roll Forward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ (20,082)		$ (25,783)
Other comprehensive income (loss) before reclassifications	20,448		(1,372)
Amounts reclassified from accumulated other comprehensive income	(7,317)		1,404
Net current-period other comprehensive income	13,131		32
Balance at end of period	(6,951)		(25,751)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			(469)
Other comprehensive income (loss) before reclassifications			16
Amounts reclassified from accumulated other comprehensive income			252
Net current-period other comprehensive income			268
Net unrealized losses on qualifying cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(290)		(5,654)
Other comprehensive income (loss) before reclassifications	2		(1,046)
Amounts reclassified from accumulated other comprehensive income	602		852
Net current-period other comprehensive income	604		(194)
Balance at end of period	314		(201)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	7,299
Other comprehensive income (loss) before reclassifications	18,274
Amounts reclassified from accumulated other comprehensive income	(8,203)
Net current-period other comprehensive income	10,071
Balance at end of period	17,370		(5,848)
Net unrecognized losses related to pension and severance plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(27,091)	[1]	(19,660)	[2]
Other comprehensive income (loss) before reclassifications	2,172		(342)
Amounts reclassified from accumulated other comprehensive income	284		300
Net current-period other comprehensive income	2,456		(42)
Balance at end of period	(24,635)	[1]	(19,702)	[1]
Deferred Tax Liabilities, Other Comprehensive Income	$ 1		$ 0		$ 0	$ 1

[1] (1) Net of deferred tax asset of $521 thousand and $401 thousand as of March 31, 2015 and December 31, 2014, respectively.

[2] (1) Net of deferred tax liability of $271 thousand and $530 thousand as of March 31, 2014 and December 31, 2013, respectively.