Investment Securities - Portfolio of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 317,251	$ 312,584
Gross Unrealized Gains	919
Gross Unrealized Losses	9,233
Fair Value	308,937
Amortized Cost		312,584
Gross Unrealized Gains		1,961
Gross Unrealized Losses		5,354
Fair Value		309,191
Obligations of state and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	20,473
Gross Unrealized Gains	82
Gross Unrealized Losses	746
Fair Value	19,809
Amortized Cost		23,042
Gross Unrealized Gains		209
Gross Unrealized Losses		442
Fair Value		22,809
GSE mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	53,195
Gross Unrealized Gains	416
Gross Unrealized Losses	1,093
Fair Value	52,518
Amortized Cost		58,620
Gross Unrealized Gains		825
Gross Unrealized Losses		321
Fair Value		59,124
Collateralized mortgage obligations: residential
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	215,868
Gross Unrealized Gains	85
Gross Unrealized Losses	7,239
Fair Value	208,714
Amortized Cost		202,573
Gross Unrealized Gains		90
Gross Unrealized Losses		4,508
Fair Value		198,155
Collateralized mortgage obligations: commercial
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,149
Gross Unrealized Gains	0
Gross Unrealized Losses	48
Fair Value	2,101
Amortized Cost		2,274
Gross Unrealized Gains		0
Gross Unrealized Losses		34
Fair Value		2,240
Mutual funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		2,100
Gross Unrealized Gains		0
Gross Unrealized Losses		39
Fair Value		2,061
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	25,566
Gross Unrealized Gains	336
Gross Unrealized Losses	107
Fair Value	$ 25,795
Amortized Cost		23,975
Gross Unrealized Gains		837
Gross Unrealized Losses		10
Fair Value		$ 24,802

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
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