FAIR VALUE MEASUREMENTS (Details) (USD $)	12 Months Ended						12 Months Ended				12 Months Ended
	Dec. 31, 2011 Days	Dec. 31, 2010	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2010 Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2010 Significant Other Observable Inputs (Level 2) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Significant Unobservable Inputs (Level 3) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2010 Significant Unobservable Inputs (Level 3) Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Total Fair Value, Measurements, Recurring [Member]	Dec. 31, 2010 Total Fair Value, Measurements, Recurring [Member]	Dec. 31, 2011 Auction Rate Securities [Member]	Dec. 31, 2011 Peak Energy Services Ltd.'s (Peak) [Member]	Jun. 10, 2011 Peak Energy Services Ltd.'s (Peak) [Member]	Dec. 31, 2011 Senior Notes [Member]	Dec. 31, 2010 Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Temporary decline in fair value of securities											$ 500,000
Unrealized pre-tax gain (loss) on auction rate securities											200,000
Interest rate, resetting days	28
Auction rate securities	4,245,000	5,437,000	0	0	0	0	4,245,000	5,437,000	4,245,000	5,437,000
Marketable securities	111,000	3,174,000	111,000	3,174,000	0	0	0	0	111,000	3,174,000
Percentage of outstanding common shares of acquiree already owned by company (as a percent)												3.15%	3.15%
Long-term Debt, Fair Value														538,500,000	278,300,000
Changes in the entity's auction rate securities measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Balance at the beginning of the period							5,437,000	6,503,000
Sale of auction rate securities at par							(1,000,000)	(1,300,000)			1,000,000
Unrealized gain (loss) included in other comprehensive income							(192,000)	234,000
Balance at the end of the period							$ 4,245,000	$ 5,437,000