Accumulated Other Comprehensive Income (Loss) (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs included in cost of product sold (2)	$ 294,960	$ 313,422	$ 604,529	$ 616,365
Amortization of prior service costs included in selling, general and administrative expenses (2)	12,511	12,483	23,760	24,924
Total before tax	63,139	6,091	68,111	28,302
Post retirement medical plan | Amount Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs included in cost of product sold (2)	264	209	528	418
Amortization of prior service costs included in selling, general and administrative expenses (2)	49	38	98	76
Total before tax	313	247	626	494
Tax Benefit	(116)	(89)	(232)	(178)
Amounts reclassified from AOCI	$ 197	$ 158	$ 394	$ 316