Available-For-Sale Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 109,950	$ 4,040
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	(544)	(17)
Available-for-sale Securities, 12 Months or Longer, Fair Value	119,438	146,382
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	(10,027)	(12,240)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	229,388	150,422
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(10,571)	(12,257)
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value	8,126	1,112
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	(48)	(8)
Available-for-sale Securities, 12 Months or Longer, Fair Value	10,393	25,007
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	(309)	(684)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	18,519	26,119
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(357)	(692)
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value	4,441
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	(5)
Available-for-sale Securities, 12 Months or Longer, Fair Value	23,922	29,448
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	(746)	(1,017)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	28,363	29,448
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(751)	(1,017)
Single Issue Trust Preferred Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, 12 Months or Longer, Fair Value	47,832	46,137
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	(8,050)	(9,685)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	47,832	46,137
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(8,050)	(9,685)
Corporate securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value	70,333
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	(238)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	70,333
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(238)
Mortgage-backed Agency securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value	27,050	2,778
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	(253)	(3)
Available-for-sale Securities, 12 Months or Longer, Fair Value	37,291	45,790
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	(922)	(854)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	64,341	48,568
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,175)	(857)
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less than 12 Months, Fair Value		150
Available-for-sale Securities, Less than 12 Months, Unrealized Losses		(6)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		150
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (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
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&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=27724398&loc=d3e27337-111563

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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.

+ 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=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Topic 320
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Section 50
-Paragraph 6
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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