Other Comprehensive Income Reclassifications from Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Prior-service costs	$ (17)		$ (17)		$ (53)		$ (51)
Actuarial losses	118		249		363		746
Total, before tax	12,037		(9,347)		38,958		4,998
Tax benefit (provision)	(4,484)		2,589		(11,679)		3,936
Total, net of tax	7,553		(6,758)		27,279		8,934
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Out Of Accumulated Other Comprehensive Income [Line Items]
Total, net of tax	(98)	[1]	(185)	[1]	(314)	[1]	(554)	[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	(17)	[1],[2]	(17)	[1],[2]	(53)	[1],[2]	(51)	[1],[2]
Actuarial losses	(118)	[1],[2]	(249)	[1],[2]	(363)	[1],[2]	(746)	[1],[2]
Other	(6)	[1],[2]	0	[1],[2]	(35)	[1],[2]	0	[1],[2]
Total, before tax	(141)	[1]	(266)	[1]	(451)	[1]	(797)	[1]
Tax benefit (provision)	43	[1]	81	[1]	137	[1]	243	[1]
Total, net of tax	$ (98)	[1]	$ (185)	[1]	$ (314)	[1]	$ (554)	[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.