STOCK-BASED COMPENSATION (Details) (USD $)	9 Months Ended		96 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Dec. 31, 2012
Weighted Average Grant Price [Roll Forward]
Stock compensation expense	$ 2,150,000	$ 1,491,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights	The shares of restricted stock granted to employees and that are outstanding as of September 30, 2013 vest in accordance with one of the following vesting schedules: 100% one year after date of grant; 33.3% each year for three years after date of grant; 20% each year for five years after the grant date; or 10% each year for ten years after the grant date.
Numerator used for calculating the number of whole shares granted	75,000
Award vesting period	1 year
Number of shares authorized for grants (in shares)	800,000
Number of shares granted (in shares)	(96,788)		(785,159)
Number of shares forfeited (in shares)	28,911		108,909
Number of shares available for future grants (in shares)	123,750
Weighted-average grant price of granted shares (in dollars per share)	$ 51.08		$ 23.49
Restricted Stock [Roll Forward]
Non-vested, beginning balance (in shares)	210,654
Granted (in shares)	96,788		785,159
Forfeited (in shares)	(28,911)		(108,909)
Vested (in shares)	(44,670)
Nonvested, ending balance (in shares)	233,861
Weighted Average Grant Price [Roll Forward]
Non vested, beginning balance (in dollars per share)	$ 26.85
Granted (in dollars per share)	$ 51.08		$ 23.49
Forfeitures (in dollars per share)	$ 37.15
Vested (in dollars per share)	$ 26.46
Nonvested, ending balance (in dollars per share)	$ 35.26
Stock compensation expense	2,100,000	1,500,000
Related income tax benefits recognized	800,000	600,000
Unrecognized compensation expense	$ 6,400,000			$ 5,500,000
Compensation cost not yet recognized, Period for recognition	28 months 3 days