Other Comprehensive Income Reclassifications from Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Prior-service costs	$ (18)		$ (17)
Actuarial losses	123		251
Total, before tax	(771)		253
Tax benefit (provision)	653		3,243
Total, net of tax	(118)		3,496
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Total, net of tax	(99)	[1]	(186)	[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	(18)	[1],[2]	(17)	[1],[2]
Actuarial losses	(123)	[1],[2]	(251)	[1],[2]
Total, before tax	(141)	[1]	(268)	[1]
Tax benefit (provision)	42	[1]	82	[1]
Total, net of tax	$ (99)	[1]	$ (186)	[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.