Pension and Other Postretirement Benefit Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Components of net periodic benefit cost [Abstract]
Defined benefit plans employer contributions toward sponsored pension plans	$ 1,700,000
Anticipated contribution during current fiscal year	9,700,000
Aggregate contribution towards sponsored pension plans	11,400,000
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost-benefits earned during the period	286,000	517,000
Interest cost on projected benefit obligation	2,624,000	2,831,000
Expected return on plan assets	(2,988,000)	(2,988,000)
Amortization of prior service (credit) cost	11,000	11,000
Amortization of (gain)/loss	663,000	270,000
Total benefits cost charged to income	596,000	641,000
Other Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost-benefits earned during the period	142,000	115,000
Interest cost on projected benefit obligation	890,000	974,000
Expected return on plan assets	0	0
Amortization of prior service (credit) cost	0	0
Amortization of (gain)/loss	26,000	(8,000)
Total benefits cost charged to income	$ 1,058,000	$ 1,081,000