Compensation Plans Non Stock-based Compensation (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Document Period End Date	Mar. 31, 2014
Cash Bonus Plan [Member]
Cash Paid in Current Period for Bonus Compensation	$ 41,700,000	$ 16,000,000
Accrued Cash Bonus Plan Expense	6,600,000	5,600,000
Net Profits Plan [Member]
General and administrative expense	2,978,000	3,786,000
Exploration expense	288,000	374,000
Total	$ 3,266,000	$ 4,160,000