RELATED PARTY TRANSACTIONS (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Related Party Transaction
Payments to retire convertible senior notes		$ 34,615,000	$ 24,865,000
Gain (loss) on early extinguishment of debt		(54,000)	346,000
3.75% Convertible Senior Notes
Related Party Transaction
Amount of debt retired		34,600,000	25,400,000
Payments to retire convertible senior notes		34,600,000	24,900,000
Gain (loss) on early extinguishment of debt		(54,000)	346,000
Debt discount at extinguishment		77,000	158,000
Haverford-Valley, L.C.
Related Party Transaction
Reimbursement of travel related expenses	93,000	122,000	139,000
Affiliated Entity
Related Party Transaction
Minimum beneficial ownership in the entity (as a percent)		5.00%
Chou or an affiliate of Chou | 3.75% Convertible Senior Notes
Related Party Transaction
Amount of debt retired		10,100,000
Fairfax or an affiliate of Fairfax | 3.75% Convertible Senior Notes
Related Party Transaction
Amount of debt retired		$ 21,700,000