SECURITIES (Narrative) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Schedule of Investments [Line Items]
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, net of deferred taxes	$ 10,054,000		$ 12,943,000
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, deferred taxes	5,400,000		7,000,000
Investment securities with unrealized losses that are considered temporary	203,048,000		124,054,000
Number of investment securities which had unrealized losses for twelve months or longer	14
Investment securities with unrealized losses for twelve months or longer	7,740,000		8,174,000
Loss on investments	138,000	121,000
Other than temporary impairment losses		29,000
Security pledged as collateral, amortized cost	450,800,000		465,000,000
Security pledged as collateral, fair value	464,200,000		482,400,000
Private issue collateralized mortgage obligations
Schedule of Investments [Line Items]
Investment securities with unrealized losses that are considered temporary	7,885,000		8,174,000
Investment securities with unrealized losses for twelve months or longer	7,725,000		8,174,000
Mortgage-backed securities
Schedule of Investments [Line Items]
Investment securities with unrealized losses that are considered temporary	70,038,000		42,782,000
Investment securities with unrealized losses for twelve months or longer	$ 15,000