STOCK-BASED COMPENSATION (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Compensation Plan disclosure [Abstract]
Stock-based compensation cost	$ 5,540,000	$ 4,447,000	$ 2,787,000
Minimum [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Maximum [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Award Recipient Type Employee [Member] | Restricted Stock [Member]
Stock Compensation Plan disclosure [Abstract]
Stock-based compensation cost	5,087,000	4,087,000	2,486,000
Stock based compensation cost capitalized as development costs	1,253,000	920,000	304,000
Share awards granted (in shares)	112,099	111,732	79,491
Grant date fair value of shares issued (in dollars per share)	$ 56.77	$ 48.79	$ 44.99
Compensation is recognized over a weighted average period (in years)	2 years 11 months 6 days
Share based compensation, share based payment arrangements other than stock options, unrecognized cost associated with awards not yet vested	8,596,000
Shares withheld to satisfy the tax obligations (in shares)	9,412	36,195	3,564
Fair value of shares granted	6,364,000	5,451,000	3,576,000
Fair value of shares vested as of the vesting date	1,700,000	6,630,000	613,000
Restricted Stock Activity [Roll Forward]
Unvested at beginning of year (in shares)	212,206	235,929	170,575
Granted (in shares)	112,099	111,732	79,491
Forfeited (in shares)	0	0	233
Vested (in shares)	(30,316)	(135,455)	(13,904)
Unvested at end of year (in shares)	293,989	212,206	235,929
Restricted stock activity weighted average price [Abstract]
Unvested at beginning of year (in dollars per share)	$ 42.84	$ 38.90	$ 36.29
Granted (in dollars per share)	$ 56.77	$ 48.79	$ 44.99
Forfeited (in dollars per share)	$ 0.00	$ 0.00	$ 35.85
Vested (in dollars per share)	$ 52.32	$ 40.88	$ 41.77
Unvested at end of year (in dollars per share)	$ 47.17	$ 42.84	$ 38.90
Nonvested Shares Vesting Schedule [Abstract]
2014 (in shares)	80,579
2015 (in shares)	73,066
2016 (in shares)	65,117
2017 (in shares)	23,037
2018 (in shares)	16,190
2019 (in shares)	16,200
2020 (in shares)	19,800
Total Nonvested Shares (in shares)	293,989	212,206	235,929
Award Recipient Type Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual Director Retainer Stock Award Amount	70,000
Stock Compensation Plan disclosure [Abstract]
Stock-based compensation cost	395,000	330,000	270,000
Employee Stock Option [Member]
Stock Compensation Plan disclosure [Abstract]
Intrinsic value realized by employees or directors from the exercise of options			5,000
Stock Options [Roll Forward]
Outstanding at beginning of year (in shares)	0	0	250
Exercised (in shares)	0	0	(250)
Outstanding at end of year (in shares)	0	0	0
Exercisable at end of year (in shares)	0	0	0
Stock Options weighted average price [Abstract]
Outstanding at beginning of year (in dollars per share)	$ 0.00	$ 0.00	$ 25.30
Exercised (in dollars per share)	$ 0.00	$ 0.00	$ 25.30
Outstanding at end of year (in dollars per share)	$ 0	$ 0.00	$ 0.00
Stock options exercisable [Abstract]
Exercisable at end of year (in dollars per share)	$ 0	$ 0.00	$ 0.00
Directors Equity Plan 2005 [Member]
Stock Compensation Plan disclosure [Abstract]
Authorized shares of common stock (in shares)	50,000
Management Incentive Plan 2004 [Member]
Stock Compensation Plan disclosure [Abstract]
Authorized shares of common stock (in shares)	1,900,000
Shares available for grant (in shares)		1,330,619	1,406,156
Management Incentive Plan 2004 [Member] | Restricted Stock [Member] | Company Performance Awards [Member] | Executive Officers [Member]
Stock Compensation Plan disclosure [Abstract]
Share awards granted (in shares)	36,813
Grant date fair value of shares issued (in dollars per share)	$ 57.10
Percentage of initial share grant vesting (in hundredths)	20.00%
Percentage of shares granted vesting annually in future periods (in hundredths)	20.00%
Restricted Stock Activity [Roll Forward]
Granted (in shares)	36,813
Restricted stock activity weighted average price [Abstract]
Granted (in dollars per share)	$ 57.10
Management Incentive Plan 2004 [Member] | Restricted Stock [Member] | Shareholder Return Awards [Member] | Executive Officers [Member]
Stock Compensation Plan disclosure [Abstract]
Share awards granted (in shares)	54,336
Grant date fair value of shares issued (in dollars per share)	$ 57.11
Percentage of initial share grant vesting (in hundredths)	25.00%
Percentage of shares granted vesting annually in future periods (in hundredths)	25.00%
Restricted Stock Activity [Roll Forward]
Granted (in shares)	54,336
Restricted stock activity weighted average price [Abstract]
Granted (in dollars per share)	$ 57.11
Equity Incentive Plan 2013 [Member]
Stock Compensation Plan disclosure [Abstract]
Authorized shares of common stock (in shares)	2,000,000
Shares available for grant (in shares)	1,971,164
Equity Incentive Plan 2013 [Member] | Award Recipient Type Employee [Member] | Restricted Stock [Member] | Non-executive officers [Member]
Stock Compensation Plan disclosure [Abstract]
Share awards granted (in shares)	20,950
Grant date fair value of shares issued (in dollars per share)	$ 55.34
Restricted Stock Activity [Roll Forward]
Granted (in shares)	20,950
Restricted stock activity weighted average price [Abstract]
Granted (in dollars per share)	$ 55.34
Stock options exercisable [Abstract]
Share Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vesting Rights (% vesting per year in future years)	20.00%
Equity Incentive Plan 2013 [Member] | Award Recipient Type Employee [Member] | Restricted Stock [Member] | Company Performance Awards [Member] | Executive Officer [Member]
Stock Compensation Plan disclosure [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (maximum)	42,780
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (minimum)	0
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%
Equity Incentive Plan 2013 [Member] | Award Recipient Type Employee [Member] | Restricted Stock [Member] | Shareholder Return Awards [Member] | Executive Officer [Member]
Stock Compensation Plan disclosure [Abstract]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (maximum)	45,288
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other Than Options, Potential Grants in Future Period (minimum)	0
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%
Equity Incentive Plan 2013 [Member] | Award Recipient Type Director [Member] | Restricted Stock [Member]
Stock Compensation Plan disclosure [Abstract]
Share awards granted (in shares)	417
Grant date fair value of shares issued (in dollars per share)	$ 59.97
Restricted Stock Activity [Roll Forward]
Granted (in shares)	417
Restricted stock activity weighted average price [Abstract]
Granted (in dollars per share)	$ 59.97
Stock options exercisable [Abstract]
Share Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vesting Rights (% vesting per year in future years)	25.00%
Director stock option [Member]
Stock Compensation Plan disclosure [Abstract]
Intrinsic value realized by employees or directors from the exercise of options	172,000	116,000	183,000
Stock Options [Roll Forward]
Outstanding at beginning of year (in shares)	4,500	9,000	18,000
Exercised (in shares)	(4,500)	(4,500)	(9,000)
Outstanding at end of year (in shares)	0	4,500	9,000
Exercisable at end of year (in shares)	0	4,500	9,000
Stock Options weighted average price [Abstract]
Outstanding at beginning of year (in dollars per share)	$ 26.60	$ 25.31	$ 24.33
Exercised (in dollars per share)	$ 26.60	$ 24.02	$ 23.36
Outstanding at end of year (in dollars per share)	$ 0.00	$ 26.60	$ 25.31
Stock options exercisable [Abstract]
Exercisable at end of year (in dollars per share)	$ 0.00	$ 26.60	$ 25.31
Award Recipient Type Director [Member]
Stock Compensation Plan disclosure [Abstract]
Shares issued to directors (in shares)	7,469	7,326	6,618
New Director Stock Awards to be Issued in Future Periods [Member] | Award Recipient Type Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Director Restricted Stock Award Amount to be Awarded in Future Periods	$ 25,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years