Pension and Other Postemployment Benefits (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension and other postemployment benefit plans			$ 57,400,000
Future contributions to pension and other postemployment benefit plans			1,300,000
Defined Benefit Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	3,701,000	3,102,000	10,981,000	8,833,000
Interest cost	8,272,000	7,558,000	24,547,000	22,253,000
Expected return on plan assets	(10,479,000)	(9,658,000)	(31,094,000)	(28,686,000)
Amortization of net loss	4,947,000	7,171,000	14,684,000	20,797,000
Amortization of prior service credit	(1,134,000)	(1,194,000)	(3,366,000)	(3,543,000)
Total net pension cost and other postemployment benefit cost	5,307,000	6,979,000	15,752,000	19,654,000
Other Postemployment Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	272,000	365,000	809,000	1,072,000
Interest cost	774,000	757,000	2,297,000	2,194,000
Amortization of net loss	(40,000)	0	(119,000)	0
Amortization of prior service credit	(8,000)	(37,000)	(24,000)	(110,000)
Total net pension cost and other postemployment benefit cost	$ 998,000	$ 1,085,000	$ 2,963,000	$ 3,156,000