Pension and Postretirement Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 789	$ 605	$ 2,355	$ 1,843
Defined Benefit Plan, Interest Cost	1,394	1,442	4,172	4,369
Defined Benefit Plan, Expected Return on Plan Assets	(1,476)	(1,358)	(4,417)	(4,101)
Defined Benefit Plan, Amortization of Losses	989	687	2,961	2,067
Defined Benefit Plan, Amortization of Prior Service Cost	23	28	155	84
Defined Benefit Plan, Net Periodic Benefit Cost	1,719	1,404	5,226	4,262
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year					6,610
Defined Benefit Plan, Contributions by Employer			5,556
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	9	5	26	14
Defined Benefit Plan, Interest Cost	46	71	138	213
Defined Benefit Plan, Expected Return on Plan Assets	0	0	0	0
Defined Benefit Plan, Amortization of Losses	8	31	24	92
Defined Benefit Plan, Amortization of Prior Service Cost	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	63	107	188	319
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year					719
Defined Benefit Plan, Contributions by Employer			$ 461