SECURITIES (Narrative) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($) security	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) security	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) security
Schedule of Investments [Line Items]
Net unrealized gains (losses) on available-for-sale securities, net of tax	$ 6,595,000		$ 6,595,000		$ (3,801,000)
Deferred Tax Liabilities,Unrealized Gains on Available-for-sale Securities,Gross	$ 3,600,000		3,600,000
Deferred tax assets, unrealized losses on available for sale securities					$ 2,000,000
Payments to acquire investments			$ 140,700,000	$ 136,700,000
AFS securities in unrealized loss positions, number of positions | security	32		32		109
AFS and HTM securities in Continues Unrealized Loss Position	$ 149,400,000		$ 149,400,000		$ 546,000,000
AFS and HTM Securities Unrealized Loss Accumulated in Investments	1,100,000		1,100,000		10,200,000
Fair Value - 12 Months of More	$ 111,341,000		$ 111,341,000		$ 192,809,000
Unrealized Loss as a Percent of Fair Value	1.00%		1.00%		2.00%
Proceeds from Sale of Available-for-sale Securities	$ 0	$ 12,426,000	$ 84,000	12,426,000
Available-for-sale Securities, Gross Unrealized Gain (Loss)		4,000		4,000
Available-for-sale Securities, Gross Realized Gains	0	221,000	4,000	221,000
Investment securities sold, carrying amount		0
Federal Home Loan Bank Stock	17,800,000		17,800,000		$ 20,600,000
Federal Reserve Bank Stock	5,400,000		5,400,000		908,000
Security pledged as collateral, amortized cost	594,900,000		594,900,000		577,600,000
Security pledged as collateral, fair value	602,200,000		602,200,000		570,900,000
Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
AFS and HTM Securities Unrealized Loss Accumulated in Investments	966,000		966,000		6,700,000
Fair Value - 12 Months of More	$ 111,300,000		$ 111,300,000		$ 192,800,000
AFS securities in unrealized loss positions, number of positions greater than or equal to one year | security	30		30		28
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Schedule of Investments [Line Items]
Fair Value - 12 Months of More	$ 32,128,000		$ 32,128,000		$ 45,629,000
Proceeds from Sale of Available-for-sale Securities		7,300,000
Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Fair Value - 12 Months of More	$ 79,213,000		79,213,000		$ 147,180,000
Available-for-sale Securities, Gross Realized Gains		4,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net		$ 204,000
Available-for-sale Securities
Schedule of Investments [Line Items]
Payments to acquire investments			130,300,000	81,300,000
Held-to-maturity Securities
Schedule of Investments [Line Items]
Payments to acquire investments			$ 10,400,000	$ 55,400,000