SUBSEQUENT EVENTS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012 8.375% senior notes	Jul. 31, 2011 8.375% senior notes	Mar. 31, 2013 Credit Agreement	Dec. 31, 2012 Credit Agreement	Dec. 31, 2011 Credit Agreement	Jun. 30, 2011 Credit Agreement	Dec. 31, 2010 Credit Agreement	Mar. 31, 2013 Credit Agreement Maturity by December 2013	Mar. 31, 2013 Credit Agreement Maturity by December 2015	Mar. 31, 2013 Subsequent event 8.375% senior notes	Mar. 31, 2013 Subsequent event Credit Agreement	Mar. 31, 2013 Subsequent event Credit Agreement Maturity by December 2013	Mar. 31, 2013 Subsequent event Credit Agreement Maturity by December 2015
SUBSEQUENT EVENTS
Interest rate (as a percent)	8.375%	8.375%								8.375%
Maximum borrowings			$ 75,000	$ 129,500	$ 129,500	$ 200,000	$ 129,500	$ 18,750	$ 56,250		$ 75,000	$ 18,750	$ 56,250
Principal amount										10,000
Aggregate purchase price										$ 9,602