Securities Available for Sale - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	$ (1,355)
Less Than Twelve Months, Fair Value	37,311
Over Twelve Months, Gross Unrealized Losses	(14)
Over Twelve Months, Fair Value	1,473
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(1,348)
Less Than Twelve Months, Fair Value	36,773
Over Twelve Months, Gross Unrealized Losses	(14)	$ (312)
Over Twelve Months, Fair Value	1,473	17,318
Debt Securities [Member] \| US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(10)
Less Than Twelve Months, Fair Value	1,990
Over Twelve Months, Gross Unrealized Losses		(12)
Over Twelve Months, Fair Value		1,989
Debt Securities [Member] \| Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(14)
Less Than Twelve Months, Fair Value	519
Over Twelve Months, Gross Unrealized Losses	(4)	(48)
Over Twelve Months, Fair Value	996	2,088
Debt Securities [Member] \| Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(46)
Less Than Twelve Months, Fair Value	3,310
Over Twelve Months, Gross Unrealized Losses	(10)	(24)
Over Twelve Months, Fair Value	477	2,185
Debt Securities [Member] \| Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(580)
Less Than Twelve Months, Fair Value	16,261
Over Twelve Months, Gross Unrealized Losses		(120)
Over Twelve Months, Fair Value		5,994
Debt Securities [Member] \| Commercial Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(554)
Less Than Twelve Months, Fair Value	8,766
Over Twelve Months, Gross Unrealized Losses		(108)
Over Twelve Months, Fair Value		$ 5,062
Debt Securities [Member] \| Collateralized Mortgage Obligations, US Government Guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(144)
Less Than Twelve Months, Fair Value	5,927
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(7)
Less Than Twelve Months, Fair Value	$ 538

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months.

+ References

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- Definition

This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

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