EMPLOYEE BENEFITS (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Estimated future pension and SERP payments
2013	$ 560,186,000
2014	606,708,000
2015	657,058,000
2016	740,152,000
2017	900,932,000
Following 5 years	7,103,618,000
401(k) Plan
Period of service required to be completed by newly hired employees	6 months
Cash contributions by the Bank	263,000	253,000	243,000
Pension Benefits
Employee benefits
Total plan assets	17,125,000	13,403,000	11,023,000
Expected contribution of the company during 2012	2,000,000
Carrying Value | Recurring basis
Employee benefits
Total plan assets	17,125,000	13,403,000
Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	9,296,000	8,342,000
Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	7,829,000	5,061,000
Cash and Cash Equivalents | Carrying Value | Recurring basis
Employee benefits
Total plan assets	1,615,000	2,899,000
Cash and Cash Equivalents | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	24,000	2,563,000
Cash and Cash Equivalents | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	1,591,000	336,000
Cash | Carrying Value | Recurring basis
Employee benefits
Total plan assets	24,000	2,563,000
Cash | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	24,000	2,563,000
Short term investment funds | Carrying Value | Recurring basis
Employee benefits
Total plan assets	1,591,000	336,000
Short term investment funds | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	1,591,000	336,000
Equity Securities | Carrying Value | Recurring basis
Employee benefits
Total plan assets	9,272,000	5,779,000
Equity Securities | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	9,272,000	5,779,000
U.S. Large cap | Carrying Value | Recurring basis
Employee benefits
Total plan assets	8,075,000	3,388,000
U.S. Large cap | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	8,075,000	3,388,000
U.S. Mid cap | Carrying Value | Recurring basis
Employee benefits
Total plan assets	596,000	326,000
U.S. Mid cap | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	596,000	326,000
U.S. Small cap | Carrying Value | Recurring basis
Employee benefits
Total plan assets		326,000
U.S. Small cap | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets		326,000
International | Carrying Value | Recurring basis
Employee benefits
Total plan assets	601,000	1,739,000
International | Quoted Prices In Active Markets for Identical Assets (Level 1) | Recurring basis
Employee benefits
Total plan assets	601,000	1,739,000
Fixed income securities | Carrying Value | Recurring basis
Employee benefits
Total plan assets	6,238,000	4,725,000
Fixed income securities | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	6,238,000	4,725,000
Government issues | Carrying Value | Recurring basis
Employee benefits
Total plan assets	1,717,000	1,589,000
Government issues | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	1,717,000	1,589,000
Corporate bonds | Carrying Value | Recurring basis
Employee benefits
Total plan assets	1,396,000	1,078,000
Corporate bonds | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	1,396,000	1,078,000
High yield bonds and bond funds | Carrying Value | Recurring basis
Employee benefits
Total plan assets	3,125,000	2,058,000
High yield bonds and bond funds | Significant Other Observable Inputs (Level 2) | Recurring basis
Employee benefits
Total plan assets	$ 3,125,000	$ 2,058,000