Stockholders' Equity - Reclassification out of Accumulated Other Comprehensive Income (Loss) (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 Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income Tax Expense (Benefit)	$ 2,623	$ (3,567)	$ (870)		$ (10,143)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			64
Unrealized Gains on Investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax			52		72
Income Tax Expense (Benefit)			(20)		(27)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			32		45
Unrecognized Net Actuarial Loss and Service Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax			(705)	[1]	(827)	[1]
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax			757	[1]	680	[1]
Income Tax Expense (Benefit)			(20)		56
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			$ 32		$ (91)

[1] Amount included in pension expense. Refer to Note 16, Pension and Postretirement Benefits.