STOCK BASED COMPENSATION PLANS (Details) (USD $) In Thousands, except Share data, unless otherwise specified		12 Months Ended					12 Months Ended					12 Months Ended
	Dec. 31, 2012 plan	Dec. 31, 2012 Long-Term Incentive Plan Options	Dec. 31, 2012 Equity Incentive Plan	Dec. 31, 2011 Equity Incentive Plan	Dec. 31, 2010 Equity Incentive Plan	Apr. 27, 2005 Equity Incentive Plan	Dec. 31, 2012 Equity Incentive Plan Outside directors	Dec. 31, 2012 Equity Incentive Plan Restricted Stock Awards (RSAs)	Dec. 31, 2011 Equity Incentive Plan Restricted Stock Awards (RSAs)	Dec. 31, 2012 Equity Incentive Plan Restricted Stock Awards (RSAs) Director	Dec. 31, 2012 Equity Incentive Plan Restricted Stock Awards (RSAs) Outside directors	Dec. 31, 2012 Equity Incentive Plan Restricted Stock Awards (RSAs) Restricted stock awards to employees	Dec. 31, 2012 Equity Incentive Plan Stock Appreciation Rights (SARs)	Dec. 31, 2009 Equity Incentive Plan Stock Appreciation Rights (SARs) Y
STOCK-BASED COMPENSATION PLANS
Number of stockholder-approved stock-based compensation plans	2
Stock-based Compensation
Options vested on anniversary date (as a percent)		25.00%
Vesting period		4 years					12 months			12 months		48 months	48 months
Expiration period of award (in years)		P10Y											P10Y
Shares authorized to be issued under the plan						2,000,000
Awards granted (in shares)								101,236	85,426
Awards cancelled (in shares)								10,050					27,500
Weighted average grant date fair value (in dollars per share)								$ 17.97	$ 17.44
Percentage of RSAs granted to outside directors expected to vest											100.00%
Assumptions utilized to determine the grant-date fair value
Expected dividend yield (as a percent)														3.07%
Expected volatility (as a percent)														22.10%
Risk-free interest rate (as a percent)														2.84%
Expected holding period (in years)														6.75
SARs outstanding and RSAs
Stock Appreciation Rights (SAR) outstanding													333,856
Exercisable (in shares)													325,602
Weighted average fair value of shares exercisable (in dollars per share)													$ 3.66
Compensation expense
Recorded compensation costs for the RSAs and SARs			$ 1,442	$ 1,300	$ 1,077
Unrecognized future compensation expense for the RSAs and SARs			$ 1,913