STOCK-BASED COMPENSATION (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011
Option valuation assumptions for options granted
Cash received for all stock option exercises	$ 3,438,091	$ 52,995
Tax benefit realized from stock awards exercised	413,238
Stock options
STOCK-BASED COMPENSATION
Number of stock option plans	3
Number of common shares authorized to be purchased	3,250,000
Vesting rights percentage	33.33%
Expiration term	10 years
Options
Outstanding at beginning of period (in shares)	3,134,320
Granted (in shares)	367,698
Exercised (in shares)	(335,444)
Forfeited (in shares)	(280,000)
Outstanding at end of period (in shares)	2,886,574	3,134,320
Exercisable at end of period (in shares)	1,683,504
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 11.29
Granted (in dollars per share)	$ 18.53
Exercised (in dollars per share)	$ 10.25
Forfeited (in dollars per share)	$ 8.95
Outstanding at end of period (in dollars per share)	$ 12.51	$ 11.29
Exercisable at end of period (in dollars per share)	$ 13.05
Weighted Average Remaining Contractual Term
Outstanding at end of period	6 years 1 month 6 days
Exercisable at end of period	4 years 4 months 24 days
Aggregate Intrinsic Value
Outstanding at end of period (in dollars)	23,421,823
Exercisable at end of period (in dollars)	13,095,301
Nonvested Shares
Nonvested at the beginning of the period (in shares)	1,497,739
Granted (in shares)	367,698
Vested (in shares)	(382,367)
Forfeited (in shares)	(280,000)
Nonvested at the end of the period (in shares)	1,203,070	1,497,739
Weighted-Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)	$ 9.49
Granted (in dollars per share)	$ 5.38
Vested (in dollars per share)	$ 2.94
Forfeited (in dollars per share)	$ 8.95
Nonvested at the end of the period (in dollars per share)	$ 12.51	$ 9.49
Unrecognized costs
Unrecognized costs related to all stock-based awards outstanding	1,300,000
Weighted average period for recognition of unrecognized compensation costs	2 years 8 months 12 days
Option valuation assumptions for options granted
Expected volatility (as a percent)	37.03%	56.10%	56.10%
Weighted average risk free rate (as a percent)	0.85%	0.40%	0.70%
Weighted average grant date fair value per share of options granted (in dollars per share)	$ 5.38	$ 3.43	$ 3.89
Total fair value of shares vested	1,122,577	1,918,460	1,190,274
Total intrinsic value of options exercised	2,736,529	41,240
Cash received for all stock option exercises	3,438,091	52,995
Tax benefit realized from stock awards exercised	$ 957,785	$ 13,816
Stock options | Directors' Plan
Option valuation assumptions for options granted
Expected life	3 years 3 months 25 days	9 years 6 months	9 years 6 months
Stock options | Executive Plan
Option valuation assumptions for options granted
Expected life	4 years 5 months 23 days	3 years 1 month 6 days	3 years 1 month 6 days
Stock options | Employee Plan
Option valuation assumptions for options granted
Expected life	3 years 3 months 25 days	3 years 1 month 6 days	3 years 1 month 6 days