Investment Securities, Available-for-sale Securities, Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost [Abstract]
Due in one year or less	$ 10,687
Due in one year through five years	170,059
Due after five years through ten years	5,069
Amortized Cost	529,532	$ 580,705
Fair Value [Abstract]
Due in one year or less	10,649
Due in one year through five years	165,213
Due after five years through ten years	5,033
Fair Value	507,882	571,965
Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Amortized Cost [Abstract]
Securities, amortized cost	282,286
Amortized Cost	282,286	330,424
Fair Value [Abstract]
Securities, fair value	269,093
Fair Value	269,093	325,683
Small Business Administration-Guaranteed Participation Securities [Member]
Amortized Cost [Abstract]
Securities, amortized cost	61,431
Amortized Cost	61,431	68,921
Fair Value [Abstract]
Securities, fair value	57,894
Fair Value	$ 57,894	$ 67,059

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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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), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amortized cost of investment in debt security measured at fair value with change recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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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), without single maturity date and not allocated over maturity grouping.

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