Retirement Benefits (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits
Net Periodic Pension Benefit Cost:
Service cost	$ 1,596,000	$ 1,863,000	$ 4,850,000	$ 5,590,000	$ 6,713,000	$ 7,156,000
Interest cost	2,648,000	2,516,000	8,114,000	7,547,000	10,631,000	10,111,000
Expected return on plan assets	(3,185,000)	(3,107,000)	(9,829,000)	(9,321,000)	(12,936,000)	(12,398,000)
Amortization of prior service cost	105,000	133,000	314,000	399,000	447,000	531,000
Amortization of net actuarial loss	1,660,000	2,611,000	4,958,000	7,834,000	7,569,000	9,818,000
Net periodic benefit cost	2,824,000	4,016,000	8,407,000	12,049,000	12,424,000	15,218,000
Expected contributions for current year			11,300,000
SERP
Net Periodic Pension Benefit Cost:
Service cost	57,000	34,000	115,000	101,000	148,000	114,000
Interest cost	117,000	78,000	290,000	236,000	370,000	301,000
Amortization of prior service cost	(2,000)	(2,000)	(6,000)	(6,000)	(8,000)	(8,000)
Amortization of net actuarial loss	168,000	142,000	378,000	426,000	520,000	523,000
Net periodic benefit cost	340,000	252,000	777,000	757,000	1,030,000	930,000
OPEB
Net Periodic Pension Benefit Cost:
Service cost	737,000	735,000	1,950,000	2,206,000	2,686,000	2,806,000
Interest cost	1,109,000	957,000	3,270,000	2,870,000	4,226,000	3,879,000
Expected return on plan assets	(1,207,000)	(1,088,000)	(3,600,000)	(3,265,000)	(4,689,000)	(4,299,000)
Amortization of prior service cost	(253,000)	(253,000)	(758,000)	(758,000)	(1,011,000)	(1,011,000)
Amortization of net actuarial loss	268,000	565,000	725,000	1,696,000	1,291,000	2,112,000
Net periodic benefit cost	654,000	916,000	1,587,000	2,749,000	2,503,000	3,487,000
Expected contributions for current year			3,000,000
Employer contributions			$ 1,500,000
Healthcare benefits
Net Periodic Pension Benefit Cost:
Eligible age			55 years
Minimum service period for eligibility			5 years