Employee Benefit Plans (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Pension Benefits
Benefit costs
Service cost		$ (12,000)		$ 1,538,000
Interest cost	2,055,000	2,440,000	4,111,000	4,936,000
Expected asset return	(2,935,000)	(2,882,000)	(5,870,000)	(5,711,000)
Amortization of loss	148,000	20,000	296,000	242,000
Net periodic benefit cost	(732,000)	(434,000)	(1,463,000)	1,005,000
Expected company contribution					12,100,000
Company contribution			5,100,000
Other Postretirement Benefits
Benefit costs
Service cost	277,000	251,000	555,000	503,000
Interest cost	516,000	598,000	1,032,000	1,196,000
Amortization of loss	74,000	40,000	149,000	81,000
Net periodic benefit cost	$ 867,000	$ 889,000	$ 1,736,000	$ 1,780,000