Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 593,167	$ 620,594
Available-for-sale Securities, Gross Unrealized Gains	2,486	1,156
Available-for-sale Securities, Gross Unrealized Losses	(12,417)	(13,190)
Available-for-sale Securities, Fair Value	583,236	608,560
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	14,999	14,995
Available-for-sale Securities, Gross Unrealized Gains		4
Available-for-sale Securities, Gross Unrealized Losses	(136)	(79)
Available-for-sale Securities, Fair Value	14,863	14,920
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	54,248	60,180
Available-for-sale Securities, Gross Unrealized Losses	(1,290)	(1,323)
Available-for-sale Securities, Fair Value	52,958	58,857
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	33,405	16,271
Available-for-sale Securities, Gross Unrealized Gains	100	60
Available-for-sale Securities, Gross Unrealized Losses	(335)	(272)
Available-for-sale Securities, Fair Value	33,170	16,059
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	315,103	376,800
Available-for-sale Securities, Gross Unrealized Losses	(7,646)	(8,640)
Available-for-sale Securities, Fair Value	307,457	368,160
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	39,485	20,107
Available-for-sale Securities, Gross Unrealized Gains	104
Available-for-sale Securities, Gross Unrealized Losses	(75)	(174)
Available-for-sale Securities, Fair Value	39,514	19,933
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	70,964	78,954
Available-for-sale Securities, Gross Unrealized Gains	45
Available-for-sale Securities, Gross Unrealized Losses	(1,966)	(1,551)
Available-for-sale Securities, Fair Value	69,043	77,403
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,763	32,061
Available-for-sale Securities, Gross Unrealized Losses	(792)	(1,009)
Available-for-sale Securities, Fair Value	30,971	31,052
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	29,573	17,065
Available-for-sale Securities, Gross Unrealized Gains	507	350
Available-for-sale Securities, Gross Unrealized Losses	(104)	(86)
Available-for-sale Securities, Fair Value	29,976	17,329
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	3,627	4,161
Available-for-sale Securities, Gross Unrealized Gains	1,730	742
Available-for-sale Securities, Gross Unrealized Losses	(73)	(56)
Available-for-sale Securities, Fair Value	$ 5,284	$ 4,847

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

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

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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Amount of debt securities categorized neither as held-to-maturity nor trading.

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