Available-For-Sale Securities in Continuous Unrealized Loss Position (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 51,493	$ 4,040
Less than 12 Months, Unrealized Losses	(2,368)	(17)
12 Months or Longer, Fair Value	115,069	146,382
12 Months or Longer, Unrealized Losses	(8,477)	(12,240)
Fair Value	166,562	150,422
Unrealized Losses	(10,845)	(12,257)
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	13,115	1,112
Less than 12 Months, Unrealized Losses	(132)	(8)
12 Months or Longer, Fair Value	10,493	25,007
12 Months or Longer, Unrealized Losses	(450)	(684)
Fair Value	23,608	26,119
Unrealized Losses	(582)	(692)
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
12 Months or Longer, Fair Value	26,048	29,448
12 Months or Longer, Unrealized Losses	(731)	(1,017)
Fair Value	26,048	29,448
Unrealized Losses	(731)	(1,017)
Single Issue Trust Preferred Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	10,760
Less than 12 Months, Unrealized Losses	(2,183)
12 Months or Longer, Fair Value	36,328	46,137
12 Months or Longer, Unrealized Losses	(6,566)	(9,685)
Fair Value	47,088	46,137
Unrealized Losses	(8,749)	(9,685)
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	26,321
Less than 12 Months, Unrealized Losses	(49)
Fair Value	26,321
Unrealized Losses	(49)
Mortgage-backed Agency securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,297	2,778
Less than 12 Months, Unrealized Losses	(4)	(3)
12 Months or Longer, Fair Value	42,051	45,790
12 Months or Longer, Unrealized Losses	(723)	(854)
Fair Value	43,348	48,568
Unrealized Losses	(727)	(857)
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value		150
Less than 12 Months, Unrealized Losses		(6)
12 Months or Longer, Fair Value	149
12 Months or Longer, Unrealized Losses	(7)
Fair Value	149	150
Unrealized Losses	$ (7)	$ (6)

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

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

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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.

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