SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 7) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings per share
Net income as reported and available to common stockholders									$ 47,254	$ 48,828	$ 37,712
Weighted average common shares, basic									46,384,000	41,892,000	41,762,000
Dilutive common stock equivalents (treasury method)									33,000		10,000
Shares used for dilutive calculation									46,417,000	41,892,000	41,772,000
Earnings per share-basic (in dollars per share)									$ 1.02	$ 1.17	$ 0.90
Earnings per share-diluted (in dollars per share)	$ 0.12	$ 0.61	$ 0.28	$ (0.03)	$ 0.12	$ 0.71	$ 0.31	$ 0.03	$ 1.02	$ 1.17	$ 0.90
Stock Appreciation Rights (SARs)
Stock-based awards included in earnings per share
Stock Appreciation Rights (SAR) outstanding	283,856				333,856				283,856	333,856	361,356