Accumulated Other Comprehensive Income (Loss) (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs included in cost of product sold	$ 204,301	$ 164,287	$ 567,610	$ 469,938
Amortization of prior service costs included in selling, general and administrative expenses (2)	12,798	11,161	33,077	38,187
Total before tax	(2,324)	2,290	25,213	4,878
Post retirement medical plan
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	(1,821)	$ (2,703)	(5,462)	(6,157)
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	(1,522)		(4,565)	(2,828)
Amortization of prior service costs included in selling, general and administrative expenses (2)	(299)		(897)	(553)
Postretirement medical plan changes	0		0	0
Total before tax	(1,821)		(5,462)	(3,381)
Tax Benefit	0		0	(2,776)
Amounts reclassified from AOCI	$ (1,821)		$ (5,462)	(6,157)
Post retirement medical plan | Amount Reclassified from Accumulated Other Comprehensive Income | Scenario Previously Reported [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs included in cost of product sold				(2,828)
Amortization of prior service costs included in selling, general and administrative expenses (2)				(553)
Postretirement medical plan changes				42,851
Total before tax				39,470
Tax Benefit				(2,776)
Amounts reclassified from AOCI				36,694
Post retirement medical plan | Amount Reclassified from Accumulated Other Comprehensive Income | Restatement Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service costs included in cost of product sold				0
Amortization of prior service costs included in selling, general and administrative expenses (2)				0
Postretirement medical plan changes				(42,851)
Total before tax				(42,851)
Tax Benefit				0
Amounts reclassified from AOCI				$ (42,851)