Hedge Contracts (Details)	12 Months Ended							12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 EUR (€)	Dec. 31, 2011 USD ($)	May 31, 2011	Dec. 31, 2013 Current Assets [Member] USD ($)	Dec. 31, 2013 Current Liabilities [Member] USD ($)	Dec. 31, 2011 Oil Swap Contract [Member] USD ($)	Dec. 31, 2011 Natural Gas Swap Contract [Member] USD ($)	Dec. 31, 2013 Forward Sale Contract, Mexican Pesos [Member] USD ($)	Dec. 31, 2013 Forward Purchase Contract, Mexican Pesos [Member] USD ($)	Dec. 31, 2013 Forward Purchase Contract, Euros [Member] USD ($)	Dec. 31, 2013 Forward Purchase Contract, Pounds Sterling [Member] USD ($)
Derivative [Line Items]
U.S. Dollar notional amount										$ 10,332,000	$ 5,928,000	$ 7,984,000	$ 3,149,000
Traded exchange rate										13.01	13.01	1.38	1.63
Value date										Jan. 17, 2014	Jan. 17, 2014	Jan. 17, 2014	Jan. 17, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pretax gain reclassified from accumulated other comprehensive income into product sales revenue (effective portion)				1,177,000				1,177,000	0
Amount of pretax gain (loss) from change in derivative fair value recognized in other comprehensive income				(7,854,000)				(7,854,000)	0
Amount of pretax gain (loss) recognized in other income (expense) (ineffective portion)				(13,947,000)				(13,947,000)	0
Net losses associated with foreign currency derivative program	34,000
Cumulative translation adjustment for investment hedge, net of tax	1,100,000
Percentage of proved reserves sold as of May 31, 2011					79.00%
Cash paid for liquidation of hedge contract				14,200,000
Derivatives [Line Items]
Forward purchase contracts						72,000	(52,000)
Forward sale contracts							32,000
Total derivatives designated as hedging instruments	52,000
Borrowings designated as a hedge of net investment in foreign subsidiary		$ 13,800,000	€ 10,000,000