Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2012 Pension and Supplemental Executive Retirement Plans [Member]	Sep. 30, 2011 Pension and Supplemental Executive Retirement Plans [Member]	Sep. 30, 2012 Pension and Supplemental Executive Retirement Plans [Member]	Sep. 30, 2011 Pension and Supplemental Executive Retirement Plans [Member]	Sep. 30, 2012 Other Postretirement Benefits [Member]	Sep. 30, 2011 Other Postretirement Benefits [Member]	Sep. 30, 2012 Other Postretirement Benefits [Member]	Sep. 30, 2011 Other Postretirement Benefits [Member]	Oct. 31, 2012 Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 2,416,000	$ 2,229,000	$ 7,247,000	$ 6,688,000	$ 307,000	$ 273,000	$ 920,000	$ 818,000
Interest cost	4,120,000	4,025,000	12,361,000	12,074,000	286,000	338,000	857,000	1,013,000
Expected return on plan assets	(4,553,000)	(4,343,000)	(13,659,000)	(13,030,000)	(791,000)	(824,000)	(2,372,000)	(2,474,000)
Recognized net actuarial loss	1,457,000	1,002,000	4,372,000	3,008,000	199,000	157,000	599,000	473,000
Amortization of prior service cost	166,000	165,000	499,000	496,000	(1,554,000)	(1,554,000)	(4,663,000)	(4,663,000)
Net periodic benefit cost	3,606,000	3,078,000	10,820,000	9,236,000	(1,553,000)	(1,610,000)	(4,659,000)	(4,833,000)
Company Contributions									$ 15,000,000