PER SHARE DATA (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income (Numerator) [Abstract]
Income available to common shareholders	$ 34,343	$ 28,778	$ 106,322	$ 88,090
Income available to common shareholders plus assumed exercise of all outstanding share based awards	$ 34,343	$ 28,778	$ 106,322	$ 88,090
Shares (Denominator) [Abstract]
Income available to common shareholders (in shares)	96,203,000	96,052,000	96,396,000	95,906,000
Effect of dilutive share-based awards (in shares)	265,000	322,000	308,000	327,000
Income available to common shareholders plus assumed exercise all outstanding share-based awards (in shares)	96,468,000	96,374,000	96,704,000	96,233,000
Per share amount [Abstract]
Income available to common shareholders (in dollars per share)	$ 0.36	$ 0.30	$ 1.10	$ 0.92
Income available to common shareholders plus assumed exercise all outstanding share-based awards (in dollars per share)	$ 0.36	$ 0.30	$ 1.10	$ 0.92
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from diluted shares (in shares)		907,000	32,400	69,000
Weighted average exercise price of antidilutive securities (in dollars per share)		$ 23.43	$ 25.31	$ 24.89