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Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
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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

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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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