Accumulated Other Comprehensive Income (Loss) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive Income (Loss)
Amortization of prior service costs included in cost of product sold (2)	$ 312,929	$ 284,461	$ 616,362	$ 610,335
Amortization of prior service costs included in selling, general and administrative expenses (2)	12,834	12,556	26,442	27,298
Total before tax	(444)	(394)	(888)	(788)
Post retirement medical plan | Amount Reclassified from Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss)
Amortization of prior service costs included in cost of product sold (2)	371	331	741	663
Amortization of prior service costs included in selling, general and administrative expenses (2)	73	63	147	125
Total before tax	444	394	888	788
Tax benefit	(160)	(142)	(319)	(284)
Amounts reclassified from accumulated other comprehensive income	$ 284	$ 252	$ 569	$ 504