STOCK-BASED COMPENSATION PLAN (Details) (USD $)	3 Months Ended		12 Months Ended	1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Jan. 31, 2015
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of options granted	0	0
Fair value per share (in dollars per share)	$ 26.13
Expected volatility, measurement period	3 years
Service period of shares (in years)	3 years
Cost	$ 985,000	$ 739,000
Capitalized	(91,000)	(70,000)
Net Expense	894,000	669,000
Unrecognized compensation cost of awards granted under the plan	6,800,000
Weighted average period over which unrecognized compensation cost is to be recognized (in years)	2 years 1 month 6 days
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-beginning balance (in dollars per share)	$ 24.40			24.40
Weighted average fair value nonvested shares-granted during the period (in dollars per share)	$ 28.69
Weighted average fair value nonvested shares-cancelled/forfeited during the period (in dollars per share)	$ 24.13
Weighted average fair value nonvested shares-vested during the period (in dollars per share)	$ 27.26
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 26.13
Officers and Key Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares granted	151,354	136,526
Vesting period of shares (in years)	3 years
The range of the actual amount of shares that ultimately vest of the original share units granted (in hundredths)	0% to 200%
Shares outstanding (in shares)	374,766		223,876
Cost	799,000	581,000
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, beginning balance (in shares)	223,876			223,876
Granted (in shares)	151,354	136,526
Cancelled/Forfeited (in shares)	(464)
Vested (in shares)	0
Nonvested shares outstanding, ending balance (in shares)	374,766		223,876
Additional disclosures [Abstract]
Number of shares awarded during the period	0		0
Officers and Key Employees | Grant Date January 2013 - TSR
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	49,514
Fair value per share (in dollars per share)	$ 22.19
Expected volatility (in hundredths)	21.10%
Risk-free interest rate (in hundredths)	0.40%
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	49,514
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 22.19
Officers and Key Employees | Grant Date January 2013 - EPS
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	49,514
Fair value per share (in dollars per share)	$ 25.59
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	49,514
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 25.59
Officers and Key Employees | Grant Date January 2014, TSR
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	62,192
Fair value per share (in dollars per share)	$ 21.31
Expected volatility (in hundredths)	20.00%
Risk-free interest rate (in hundredths)	0.80%
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	62,192
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 21.31
Officers and Key Employees | Grant Date January 2014, EPS
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	62,192
Fair value per share (in dollars per share)	$ 27.22
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	62,192
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 27.22
Officers and Key Employees | Grant Date January 2015, TSR
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	42,378
Fair value per share (in dollars per share)	$ 26.31
Expected volatility (in hundredths)	16.00%
Risk-free interest rate (in hundredths)	1.10%
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	42,378
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 26.31
Officers and Key Employees | Grant Date January 2015, EPS, ROE, Time
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	108,976
Fair value per share (in dollars per share)	$ 29.47
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	108,976
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 29.47
Director
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares granted	25,398	23,220
Vesting period of shares (in years)	12 months
Shares Vested, Directors (in hundredths)	100.00%
Shares outstanding (in shares)	25,398
Cost	186,000	158,000
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, beginning balance (in shares)	23,220			23,220
Granted (in shares)	25,398	23,220
Cancelled/Forfeited (in shares)	0
Vested (in shares)	(23,220)
Nonvested shares outstanding, ending balance (in shares)	25,398
Additional disclosures [Abstract]
Fair value of shares issued	$ 700,000	$ 600,000
Director | Grant Date January 2015
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares outstanding (in shares)	25,398
Fair value per share (in dollars per share)	$ 29.34
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Nonvested shares outstanding, ending balance (in shares)	25,398
Additional disclosures [Abstract]
Weighted average fair value nonvested shares-ending balance (in dollars per share)	$ 29.34
Minimum | Officers and Key Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of actual amount of shares that ultimately vest of original share units granted	0.00%
Maximum | Officers and Key Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Percentage of actual amount of shares that ultimately vest of original share units granted	200.00%
Stock Appreciation Rights (SARs)
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares granted	0	0
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Granted (in shares)	0	0
Restricted Stock | Officers and Key Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Number of shares granted				45,406
Vesting period of shares (in years)	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Payout Limit, Percentage	100.00%
Restricted stock award activity, excluding accrued dividend equivalents [Roll Forward]
Granted (in shares)				45,406