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Goodwill and Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Goodwill and Intangible Assets [Line Items] |  |  |  |
Indefinite-lived Intangible Assets (Excluding Goodwill) |  | $ 919 | $ 919 | $ 919
Intangible Assets, Net (Excluding Goodwill) |  | 45,937 | 58,173 | 17,631
Goodwill and Intangible Assets [Roll Forward] |  |  |  |
Total goodwill, beginning of period |  | 765,842 | 382,762 | 382,762
Established through acquisitions | [1] | 0 | 383,080 | 0
Total goodwill, end of period |  | 765,842 | 765,842 | 382,762
Core deposit intangible, net, beginning of period |  | 58,173 |  |
CDI current period amortization |  | (12,236) | (6,333) | (5,946)
Total core deposit intangible, end of period |  | 45,937 | 58,173 |
Total goodwill and intangible assets, end of period |  | 811,779 | 824,015 | 400,393
Core Deposits [Member] |  |  |  |
Goodwill and Intangible Assets [Roll Forward] |  |  |  |
Gross core deposit intangible balance, beginning of period |  | 105,473 | 58,598 | 58,598
Accumulated amortization, beginning of period |  | (48,219) | (41,886) | (35,940)
Core deposit intangible, net, beginning of period |  | 57,254 | 16,712 | 22,658
Established through acquisitions | [1] | 0 | 46,875 | 0
CDI current period amortization |  | (12,236) | (6,333) | (5,946)
Total core deposit intangible, end of period |  | $ 45,018 | $ 57,254 | $ 16,712
Estimated life of CDI, in years |  | 10 years |  |
[1] | See Note 2, “Business Combinations,” for additional information regarding the goodwill related to the acquisition of Pacific Continental on November 1, 2017.

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 + Details
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