NET INCOME PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
NET INCOME PER COMMON SHARE
Net income	$ 8,636	$ 6,752
Shares of common stock outstanding used to compute basic per common share amounts	34,036,539	33,360,840
Effect of dilutive restricted stock and options (in shares)	603,121	773,227
Shares used to compute diluted per common share amounts	34,639,660	34,134,067
Basic income per share	$ 0.25	$ 0.20
Diluted income per share	$ 0.25	$ 0.20