EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Basic (loss)/earnings per share calculation:
Net (loss)/income to common stockholders	$ (2,623)	$ (4,042)	$ (25,109)	$ 5,649	$ 7,310	$ 5,763	$ 6,276	$ 5,011	$ (26,125)	$ 24,360	$ 16,484
Weighted average number of common shares outstanding (in shares)									22,970,000	22,955,000	23,080,000
Basic net (loss)/income per share (in dollars per share)	$ (0.11)	$ (0.18)	$ (1.09)	$ 0.25	$ 0.32	$ 0.25	$ 0.27	$ 0.22	$ (1.14)	$ 1.06	$ 0.71
Diluted (loss)/earnings per share calculation:
Net (loss)/income to common stockholders	$ (2,623)	$ (4,042)	$ (25,109)	$ 5,649	$ 7,310	$ 5,763	$ 6,276	$ 5,011	$ (26,125)	$ 24,360	$ 16,484
Weighted average number of common shares outstanding (in shares)									22,970,000	22,955,000	23,080,000
Assumed conversion of Class B Stock (in shares)									0	221,000	228,000
Effect of dilutive stock options (in shares)									0	80,000	104,000
Diluted weighted average number of common shares outstanding (in shares)									22,970,000	23,256,000	23,412,000
Diluted net (loss)/income per share (in dollars per share)	$ (0.11)	$ (0.18)	$ (1.09)	$ 0.24	$ 0.31	$ 0.25	$ 0.27	$ 0.22	$ (1.14)	$ 1.05	$ 0.70
Common stock equivalents										32,418	6,452