EARNINGS PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 15,344	$ 14,911	$ 46,401	$ 44,564
Denominator for basic earnings per share - weighted average shares	59,403,109	57,201,390	57,907,203	57,309,934
Effect of dilutive securities -
Employee stock awards	576,543	698,194	594,082	725,862
Warrants	133,280	113,004	138,109	107,576
Denominator for diluted earnings per share - adjusted weighted average shares	60,112,932	58,012,588	58,639,394	58,143,372
Basic	$ 0.26	$ 0.26	$ 0.80	$ 0.78
Diluted	$ 0.26	$ 0.26	$ 0.79	$ 0.77