GOODWILL AND OTHER INTANGIBLES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		12 Months Ended
	Dec. 31, 2012 item	Dec. 31, 2010	Dec. 31, 2011 Legacy Bancorp, Inc.	Dec. 31, 2011 Rome Bancorp, Inc.	Dec. 31, 2012 Connecticut Bank and Trust	Dec. 31, 2012 Greenpark Mortgage Corporation	Dec. 31, 2012 Beacon Federal Bancorp, Inc	Dec. 31, 2012 Other	Dec. 31, 2011 Other	Dec. 31, 2012 Banking	Dec. 31, 2011 Banking	Dec. 31, 2012 Insurance	Dec. 31, 2011 Insurance
Goodwill
Number of significant acquisitions completed	3
Goodwill
Balance, beginning of the period	$ 202,391	$ 161,725								$ 232,023	$ 179,215	$ 23,176	$ 23,176
Goodwill acquired			23,496	17,176	14,146	4,145	34,511	6	(6)
Balance, end of the period	$ 255,199	$ 161,725								$ 232,023	$ 179,215	$ 23,176	$ 23,176