Shareholders' Equity Reclassifications from Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Prior-service costs	$ (15)		$ (18)
Actuarial losses	(497)		(123)
Income (loss) before income taxes	10,928		(771)
Tax benefit (provision)	(5,563)		653
Net income (loss)	5,365		(118)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	(505)	[1]	(99)	[1]
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Prior-service costs	(15)	[1],[2]	(18)	[1],[2]
Actuarial losses	(497)	[1],[2]	(123)	[1],[2]
Income (loss) before income taxes	(512)	[1]	(141)	[1]
Tax benefit (provision)	7	[1]	42	[1]
Net income (loss)	$ (505)	[1]	$ (99)	[1]

[1] Amounts in parenthesis indicate debits to the Consolidated Statements of Operations.

[2] These AOCI components are included in the computation of net periodic pension cost. Refer to Note 8 for additional details.