Accrued Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accrued Liabilities Detail [Table]
Compensation and employee benefits	$ 12,784	$ 11,382
Oil and gas producing liabilities	15,966	31,347
Unearned income	13,160	16,073
Other accrued liabilities	39,065	28,727
Accrued liabilities	$ 80,975	$ 87,529