Investment Securities - Summary of Amortized Cost of Securities and Fair Values (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 544,054	$ 646,725
Gross unrealized gains	9,693	8,570
Gross unrealized losses	(390)	(5,908)
Available-for-sale securities, at fair value	553,357	649,387
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	535,332	637,754
Gross unrealized gains	9,667	8,567
Gross unrealized losses	(316)	(5,818)
Available-for-sale securities, at fair value	544,683	640,503
Debt Securities \| U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	2,501	34,161
Gross unrealized losses		(353)
Available-for-sale securities, at fair value	2,501	33,808
Debt Securities \| Mortgage-backed Securities - Residential
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	429,156	524,141
Gross unrealized gains	4,678	3,675
Gross unrealized losses	(270)	(5,443)
Available-for-sale securities, at fair value	433,564	522,373
Debt Securities \| Municipals, Tax Exempt
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	99,171	74,945
Gross unrealized gains	4,987	4,892
Gross unrealized losses	(46)
Available-for-sale securities, at fair value	104,112	79,837
Debt Securities \| Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	4,504	4,507
Gross unrealized gains	2
Gross unrealized losses		(22)
Available-for-sale securities, at fair value	4,506	4,485
Equity Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	8,722	8,971
Gross unrealized gains	26	3
Gross unrealized losses	(74)	(90)
Available-for-sale securities, at fair value	$ 8,674	$ 8,884

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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