Pensions and Other Postretirement Benefit Plans (Schedule of Error Correction and Reclassification of Plan Assets) (Details) (Pension Plans [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair value of plan assets	$ 183,199	$ 168,390	$ 173,434
Common Stocks and Equity Funds [Member]
Fair value of plan assets	34,624	46,360
Debt Securities [Member]
Fair value of plan assets	136,984	109,330
Insurance Contracts [Member]
Fair value of plan assets	2,133	2,875
Limited Partnerships [Member]
Fair value of plan assets	6,522	7,034
Hedge Funds [Member]
Fair value of plan assets	364	392
Cash and Short-Term Investments [Member]
Fair value of plan assets	2,572	2,399
Previously reported [Member]
Fair value of plan assets		168,390
Previously reported [Member] | Common Stocks and Equity Funds [Member]
Fair value of plan assets		33,685
Previously reported [Member] | Debt Securities [Member]
Fair value of plan assets		122,699
Previously reported [Member] | Insurance Contracts [Member]
Fair value of plan assets		2,875
Previously reported [Member] | Limited Partnerships [Member]
Fair value of plan assets		7,034
Previously reported [Member] | Hedge Funds [Member]
Fair value of plan assets		392
Previously reported [Member] | Cash and Short-Term Investments [Member]
Fair value of plan assets		1,705
Revision [Member]
Fair value of plan assets
Revision [Member] | Common Stocks and Equity Funds [Member]
Fair value of plan assets		12,675
Revision [Member] | Debt Securities [Member]
Fair value of plan assets		(13,369)
Revision [Member] | Insurance Contracts [Member]
Fair value of plan assets
Revision [Member] | Limited Partnerships [Member]
Fair value of plan assets
Revision [Member] | Hedge Funds [Member]
Fair value of plan assets
Revision [Member] | Cash and Short-Term Investments [Member]
Fair value of plan assets		$ 694