SECURITIES AVAILABLE FOR SALE - Summary of Amortized Cost and Fair Value and Corresponding Amounts of Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortized Cost
Total debt securities	$ 411,656
Equity securities	50
Totals	411,706	$ 401,919
Gross Unrealized Gains
Totals	7,496	3,138
Gross Unrealized Losses
Totals	3,894	4,903
Fair Value
Total debt securities	415,194
Equity securities	114
Totals	415,308	400,154
Debt securities
Amortized Cost
Total debt securities	411,656	401,869
Gross Unrealized Gains
Total debt securities	7,432	3,097
Gross Unrealized Losses
Total debt securities	3,894	4,903
Fair Value
Total debt securities	415,194	400,063
Debt securities \| U.S. Government Agencies
Amortized Cost
Total debt securities		39,569
Gross Unrealized Gains
Total debt securities		147
Gross Unrealized Losses
Total debt securities		124
Fair Value
Total debt securities		39,592
Debt securities \| States and political subdivisions
Amortized Cost
Total debt securities	153,803	163,677
Gross Unrealized Gains
Total debt securities	6,133	1,782
Gross Unrealized Losses
Total debt securities	478	1,177
Fair Value
Total debt securities	159,458	164,282
Debt securities \| GSE residential MBSs
Amortized Cost
Total debt securities	48,600	116,022
Gross Unrealized Gains
Total debt securities	930	928
Gross Unrealized Losses
Total debt securities	0	6
Fair Value
Total debt securities	49,530	116,944
Debt securities \| GSE residential CMOs
Amortized Cost
Total debt securities	113,658	72,411
Gross Unrealized Gains
Total debt securities	296	240
Gross Unrealized Losses
Total debt securities	2,835	3,268
Fair Value
Total debt securities	111,119	69,383
Debt securities \| GSE commercial CMOs
Amortized Cost
Total debt securities		5,148
Gross Unrealized Gains
Total debt securities		0
Gross Unrealized Losses
Total debt securities		292
Fair Value
Total debt securities		4,856
Debt securities \| Private label residential CMOs
Amortized Cost
Total debt securities	999	5,042
Gross Unrealized Gains
Total debt securities	4	0
Gross Unrealized Losses
Total debt securities	0	36
Fair Value
Total debt securities	1,003	5,006
Debt securities \| Private label commercial CMOs
Amortized Cost
Total debt securities	7,809
Gross Unrealized Gains
Total debt securities	0
Gross Unrealized Losses
Total debt securities	156
Fair Value
Total debt securities	7,653
Debt securities \| Asset-backed
Amortized Cost
Total debt securities	86,787
Gross Unrealized Gains
Total debt securities	69
Gross Unrealized Losses
Total debt securities	425
Fair Value
Total debt securities	86,431
Equity securities
Amortized Cost
Equity securities	50	50
Gross Unrealized Gains
Equity securities	64	41
Gross Unrealized Losses
Equity securities	0	0
Fair Value
Equity securities	$ 114	$ 91

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.