LONG TERM INCENTIVE PLAN & STOCK OPTIONS (Details) (USD $)	0 Months Ended	12 Months Ended							12 Months Ended					12 Months Ended								72 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Options	Dec. 31, 2011 Options	Dec. 31, 2010 Options	Dec. 31, 2009 Options	Dec. 31, 2012 Restricted shares	Dec. 31, 2010 Restricted shares	Dec. 31, 2012 Restricted shares Vesting after 18 months from the grant date	Dec. 31, 2012 Restricted shares Vesting after 36 months from the grant date	Dec. 31, 2012 LTIP	Dec. 31, 2012 LTIP Options	Dec. 31, 2011 LTIP Options	Dec. 31, 2010 LTIP Options	Dec. 31, 2012 LTIP Restricted shares	Dec. 31, 2011 LTIP Restricted shares	Dec. 31, 2010 LTIP Restricted shares	Dec. 31, 2012 LTIP Restricted shares 2012 grant	Dec. 31, 2012 LTIP Restricted shares 2010 grant	Dec. 31, 2012 Old Plan
LONG TERM INCENTIVE PLAN & STOCK OPTIONS
Number of common shares reserved for issuance													6,250,000
Options granted (in shares)					871,000	839,000	938,000															0
Expiration term					10 years									10 years
Vesting period					3 years						18 months	36 months		3 years						2 years
Percentage of awards vested																					50.00%
Vesting terms extended to March 2013																					50.00%
Vesting terms extended to August 2013																					50.00%
Additional disclosures
Restricted Shares Granted		235,000		235,000					235,000	235,000							235,000		235,000
Expense related to Grant of Restricted Shares														$ 3,903,795	$ 3,469,703	$ 3,048,750	$ 1,075,929	$ 596,000	$ 332,644
Market Value Per Share on Grant Date																	$ 9.45		$ 5.86
Unrecorded Stock Based Compensation for Restricted Stock Awards Attributable to Future Periods																	1,885,790
Minimum period for which previously issued shares are to be held by the recipient for non-cash exchange to newly issued shares					6 months
Cash proceeds received upon the exercise of options		132,026	719,484	90,448	132,026	719,484	90,448
Income tax benefits related to stock option activity	2,400,000	494,000	772,000	125,000
Excess tax benefits on share based compensation that would be credited directly to contributed capital, if recognized	2,400,000	2,400,000
SHARES
Outstanding at the beginning of the period (in shares)					5,482,135	5,289,334	4,441,500
Granted (in shares)					871,000	839,000	938,000															0
Exercised (in shares)					(223,601)	(416,201)	(78,166)
Forfeited (in shares)					(140,334)	(229,998)	(12,000)
Outstanding at the end of the period (in shares)					5,989,200	5,482,135	5,289,334
WEIGHTED AVERAGE EXERCISE PRICE
Outstanding at the beginning of the period (in dollars per share)					$ 5.23	$ 4.52	$ 3.95
Granted (in dollars per share)					$ 9.62	$ 8.54	$ 6.70
Exercised (in dollars per share)		$ 0.61	$ 1.81	$ 1.16	$ 0.59	$ 1.81	$ 1.16
Forfeited (in dollars per share)					$ 8.66	$ 6.61	$ 6.80
Outstanding at the end of the period (in dollars per share)					$ 5.95	$ 5.23	$ 4.52
AGGREGATE INTRINSIC VALUE
Outstanding (in dollars)	12,559,074	12,559,074			12,559,074	17,761,008	17,879,160	16,604,310
Exercised (in dollars)					$ 1,286,176	$ 2,571,874	$ 369,887