STOCK-BASED COMPENSATION (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense			$ (3,571,000)
Grant date fair value of shares issued (in dollars per share)	$ 0.00		$ 48.79
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at beginning of period (in shares)	276,784		235,929
Granted (in shares)	0		111,732
Forfeited (in shares)	0		0
Vested (in shares)	0		(70,877)
Unvested at end of period (in shares)	276,784		276,784
Weighted Average Grant Date Fair Value [Abstract]
Unvested at beginning of period (per share)	$ 42.28		$ 38.90
Granted (per share)	$ 0.00		$ 48.79
Forfeited (per share)	$ 0		$ 0
Vested (per share)	$ 0.00		$ 41.27
Unvested at end of period (per share)	$ 42.28		$ 42.28
Management Incentive Plan 2004 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized shares of common stock	1,900,000		1,900,000
Shares available for grant	1,312,351		1,312,351
Stock-based compensation costs capitalized as development costs	212,000	102,000	669,000	188,000
Allocated Share-based Compensation Expense	870,000	555,000	3,210,000	1,903,000
Management Incentive Plan 2004 [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld for tax obligations			17,927
Fair value of shares vested			3,191,000
Management Incentive Plan 2004 [Member] | Restricted Stock [Member] | Company Performance Awards [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (minimum)	0
Weighted Average Grant Date Fair Value [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (maximum)	51,369
Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Percent of future vesting that will occur on grant date	20.00%
Share Based Compensation Arrangement By Share Based Payment Award Possible Shares To Be Awarded Vesting Rights	20.00%
Management Incentive Plan 2004 [Member] | Restricted Stock [Member] | Shareholder Return Awards [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (minimum)	0
Weighted Average Grant Date Fair Value [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (maximum)	54,335
Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Percent of future vesting that will occur on grant date	25.00%
Share Based Compensation Arrangement By Share Based Payment Award Possible Shares To Be Awarded Vesting Rights	25.00%
Directors Equity Plan 2005 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized shares of common stock	50,000		50,000
Allocated Share-based Compensation Expense	$ 90,000	$ 75,000	$ 240,000	$ 195,000