SECURITIES (Narrative) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) security	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) security	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Schedule of Investments [Line Items]
Net unrealized gains (losses) on available-for-sale securities, net of tax	$ 2,880,000		$ 2,880,000		$ (319,000)
Deferred tax assets, unrealized losses on available for sale securities	$ 1,551,000		1,551,000		172,000
Payments to acquire investments			$ 136,700,000
AFS securities in unrealized loss positions, number of positions | security	73		73
AFS and HTM securities in continuous unrealized loss position	$ 280,700,000		$ 280,700,000
AFS and HTM Securities unrealized loss accumulated in investments	$ 4,200,000		$ 4,200,000
Unrealized Loss as a Percent of Amortized Cost	1.00%		1.00%
Fair Value - 12 Months of More	$ 203,010,000		$ 203,010,000		307,951,000
OTTI, investments, available-for-sale securities			204,000	$ 0
Investment securities sold, carrying amount		$ 0
Gain (loss) on investments	4,000	$ 0	4,000	451,000
Security pledged as collateral, amortized cost	508,900,000		508,900,000		486,200,000
Security pledged as collateral, fair value	$ 510,300,000		$ 510,300,000		485,600,000
Mortgage Backed Securities and Collateralized Mortgage Obligations
Schedule of Investments [Line Items]
AFS securities in unrealized loss positions, number of positions greater than or equal to one year | security	34		34
Fair Value - 12 Months of More	$ 203,000,000		$ 203,000,000
Private issue collateralized mortgage obligations
Schedule of Investments [Line Items]
Fair Value - 12 Months of More					0
Gain (loss) on investments	4,000
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Fair Value - 12 Months of More	57,721,000		57,721,000		$ 125,439,000
Investment securities sold, carrying amount	7,300,000
Available-for-sale Securities
Schedule of Investments [Line Items]
Payments to acquire investments			81,300,000
Investment securities sold, carrying amount	12,400,000		12,400,000	25,200,000
Gain (loss) on investments	$ 4,000		4,000	$ 451,000
Held-to-maturity Securities
Schedule of Investments [Line Items]
Payments to acquire investments			$ 55,400,000