Amortized Cost and Fair Value of Held-to-Maturity Securities, Including Gross Unrealized Gains and Losses (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 31,029	$ 568
Unrealized Gains	4	11
Unrealized Losses	(130)
Fair Value	30,903	579
U.S. Agency securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	20,045
Unrealized Losses	(87)
Fair Value	19,958
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	379	568
Unrealized Gains	3	11
Fair Value	382	579
Corporate securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	10,605
Unrealized Gains	1
Unrealized Losses	(43)
Fair Value	$ 10,563

Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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- Definition

Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

+ References

+ Details

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- Definition

Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

+ References

No definition available.

+ Details

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- Definition

Fair value of investments in debt securities classified as held-to-maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

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