Pension Benefit and Other Postretirement Benefit Plans (Additional Information) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension and Other Postretirement Benefits Disclosure [Line Items]
Employer contributions	$ 800,000	$ 0
Retirement Health and Life Insurance Benefits [Member]
Pension and Other Postretirement Benefits Disclosure [Line Items]
Settlement charge
Pension Benefits [Member]
Pension and Other Postretirement Benefits Disclosure [Line Items]
Settlement charge	110,000
Employer contributions	0	6,500,000
Former President and Chief Executive Officer [Member] | Pension Benefits [Member]
Pension and Other Postretirement Benefits Disclosure [Line Items]
Benefit payments	800,000
Settlement charge	$ 100,000