Defined Benefit Plans - Net Periodic Pension and Postretirement Benefit Costs (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 800,000		$ 1,800,000
Service costs	190,000	170,000	570,000	520,000
Interest costs	450,000	410,000	1,330,000	1,230,000
Expected return on plan assets	(510,000)	(460,000)	(1,550,000)	(1,380,000)
Amortization of prior service cost	0	0	10,000	10,000
Amortization of net (gain)/loss	270,000	320,000	830,000	960,000
Net periodic benefit cost	400,000	440,000	1,190,000	1,340,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs	0	0	0	0
Interest costs	10,000	10,000	30,000	30,000
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Amortization of net (gain)/loss	(20,000)	(20,000)	(70,000)	(60,000)
Net periodic benefit cost	$ (10,000)	$ (10,000)	$ (40,000)	$ (30,000)