Pension and Other Postretirement Benefits (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension and other postretirement benefit plans			$ 8,200,000
Future contributions to pension and other postretirement benefit plans			15,000,000
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,881,000	2,721,000	5,731,000	5,442,000
Interest cost	7,388,000	7,569,000	14,695,000	15,138,000
Expected return on plan assets	(9,567,000)	(9,367,000)	(19,028,000)	(18,734,000)
Amortization of net loss	6,852,000	7,559,000	13,626,000	13,804,000
Amortization of prior service cost	(1,181,000)	(1,158,000)	(2,349,000)	(2,317,000)
Total net pension cost and other postretirement benefit cost	6,373,000	7,324,000	12,675,000	13,333,000
Less: Discontinued operations	0	1,424,000	0	1,424,000
Continuing operations	6,373,000	5,900,000	12,675,000	11,909,000
Other Postretirement Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	355,000	457,000	707,000	915,000
Interest cost	723,000	942,000	1,437,000	1,884,000
Amortization of net loss	0	80,000	0	161,000
Amortization of transition obligation	0	119,000	0	237,000
Amortization of prior service cost	(37,000)	(36,000)	(73,000)	(73,000)
Total net pension cost and other postretirement benefit cost	$ 1,041,000	$ 1,562,000	$ 2,071,000	$ 3,124,000