Discontinued Operations Discontinued Operations (Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
CURRENT ASSETS
Cash and cash equivalents	$ 519	$ 1,715
Prepaids and other current assets	1,363	2,159
Total current assets held for sale	1,882	3,874
LONG-TERM ASSETS
Property and equipment, net	120,732	69,597
Deferred income taxes	11,245	6,238
Other assets	649	2,896
Total long-term assets held for sale	132,626	78,731
CURRENT LIABILITIES
Accrued drilling costs	3,800	3,027
Current maturities of long-term debt	33,800	0
Other accrued liabilities	11,063	1,211
Total current liabilities associated with assets held for sale	48,663	4,238
LONG-TERM LIABILITIES
Long-term debt, net of current maturities	18,200	17,814
Asset retirement obligations	5,243	3,843
Other liabilities	104	772
Total long-term liabilities associated with assets held for sale	$ 23,547	$ 22,429