STOCK-BASED COMPENSATION (Details) (USD $)	0 Months Ended	12 Months Ended
	May 21, 2014 item	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Option valuation assumptions for options granted
Cash received for all stock option exercises		$ (2,726,000)	$ 3,438,000	$ 53,000
Tax benefit realized from stock awards exercised		1,079,000	413,000
Stock options
STOCK-BASED COMPENSATION
Number of stock option plans	2
Number of common shares authorized to be purchased		1,000,000
Options
Outstanding at beginning of period (in shares)		2,886,574
Granted (in shares)		377,000
Exercised (in shares)		(1,136,371)
Forfeited (in shares)		(125,000)
Outstanding at end of period (in shares)		2,002,203	2,886,574
Exercisable at end of period (in shares)		829,060
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)		$ 12.51
Granted (in dollars per share)		$ 14.44
Exercised (in dollars per share)		$ 11.08
Forfeited (in dollars per share)		$ 11.09
Outstanding at end of period (in dollars per share)		$ 13.73	$ 12.51
Exercisable at end of period (in dollars per share)		$ 14.22
Weighted Average Remaining Contractual Term
Outstanding at end of period		7 years
Exercisable at end of period		5 years
Aggregate Intrinsic Value
Outstanding at end of period (in dollars)		8,468,661
Exercisable at end of period (in dollars)		3,887,865
Nonvested Shares
Nonvested at the beginning of the period (in shares)		1,203,070
Granted (in shares)		377,000
Vested (in shares)		(281,927)
Forfeited (in shares)		(125,000)
Nonvested at the end of the period (in shares)		1,173,143	1,203,070
Weighted-Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 12.51
Granted (in dollars per share)		$ 4.02
Vested (in dollars per share)		$ 3.24
Forfeited (in dollars per share)		$ 11.09
Nonvested at the end of the period (in dollars per share)		$ 13.73	$ 12.51
Unrecognized costs
Unrecognized costs related to all share-based awards outstanding		1,300,000
Weighted average period for recognition of unrecognized compensation costs		2 years 4 months 24 days
Option valuation assumptions for options granted
Expected volatility (as a percent)		34.95%	37.03%	56.10%
Weighted average risk free rate (as a percent)		1.06%	0.85%	0.40%
Weighted average grant date fair value per share of options granted (in dollars per share)		$ 4.02	$ 5.38	$ 3.43
Total fair value of shares vested		913,000	1,123,000	1,918,000
Total intrinsic value of options exercised		8,921,000	2,737,000	41,000
Cash received for all stock option exercises		12,595,000	3,438,000	53,000
Tax benefit realized from stock awards exercised		$ 3,122,000	$ 958,000	$ 14,000
Stock options | Maximum
STOCK-BASED COMPENSATION
Number of common shares authorized to be purchased		2,843,411
Stock options | Directors' Plan
Option valuation assumptions for options granted
Expected life		3 years 7 months 2 days	3 years 3 months 26 days	9 years 6 months
Stock options | Executives Plan
Option valuation assumptions for options granted
Expected life		4 years 3 months 22 days	4 years 5 months 23 days	3 years 1 month 6 days
Stock options | Employees Plan
Option valuation assumptions for options granted
Expected life		3 years 7 months 2 days	3 years 3 months 26 days	3 years 1 month 6 days