STOCK-BASED COMPENSATION PLANS (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stock-based compensation plans, additional disclosures
Stock-based compensation expense	$ 881	$ 466
Non-vested Stock Awards
Non-vested Stock Awards Outstanding, Number of Shares
Balance at the beginning of the period (in shares)	244
Granted (in shares)	146
Stock awards vested (in shares)	(69)	(46)
Forfeited (in shares)	(4)
Balance at the end of the period (in shares)	317
Non-vested Stock Awards Outstanding, Weighted-Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)	$ 21.69
Granted (in dollars per share)	$ 23.90
Stock awards vested (in dollars per share)	$ 18.99
Forfeited (in dollars per share)	$ 22.40
Balance at the end of the period (in dollars per share)	$ 23.29
Stock Options
Stock Options Outstanding, Number of Shares
Balance at the beginning of the period (in shares)	688
Stock options exercised (in shares)	(118)
Forfeited (in shares)	(8)
Expired (in shares)	(8)
Balance at the end of the period (in shares)	554
Exercisable options at the end of the period (in shares)	497
Stock Options Outstanding, Weighted-Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 18.13
Stock options exercised (in dollars per share)	$ 15.51
Forfeited (in dollars per share)	$ 18.24
Expired (in dollars per share)	$ 21.82
Balance at the end of the period (in dollars per share)	$ 18.64
Exercisable options at the end of the period (in dollars per share)	$ 11.78
Stock-based compensation plans, additional disclosures
Proceeds from stock option exercises	$ 1,800	$ 16