INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Finite-Lived Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Dec. 31, 2007 acquisition
Finite-Lived Intangible Assets [Line Items]
Number of Bank Acquisitions, Created Finite-Lived Intangible Asset			3
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$ 6,331	$ 8,609
Amortization	(1,591)	(2,278)
Balance, end of period	4,740	6,331
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	6,322	8,598
Amortization	(1,583)	(2,276)
Balance, end of period	4,739	6,322
Other [Member]
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	9	11
Amortization	(8)	(2)
Balance, end of period	$ 1	$ 9