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Consideration Transferred, Identifiable Net Assets Acquired and Goodwill Recognized (Details) - USD ($) |  |  |  | 12 Months Ended
--- | --- | --- | --- | ---
Feb. 28, 2018 | Jan. 31, 2018 | Apr. 30, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Fair value of consideration transferred |  |  |  |  |  |  |
Effective settlement of pre-existing receivable |  |  |  |  | $ 10,054,000 | $ 0 | $ 0
Liabilities assumed |  |  |  |  |  |  |
Goodwill recognized |  |  |  |  | $ 111,775,000 | $ 30,758,000 | $ 6,415,000
First Security Bank |  |  |  |  |  |  |
Fair value of consideration transferred |  |  |  |  |  |  |
Fair value of Company shares issued, net of equity issuance costs |  | $ 181,043,000 |  |  |  |  |
Cash consideration for outstanding shares |  | 0 |  |  |  |  |
Effective settlement of pre-existing receivable |  | 0 |  |  |  |  |
Total fair value of consideration transferred |  | 181,043,000 |  |  |  |  |
Identifiable assets acquired |  |  |  |  |  |  |
Cash and cash equivalents |  | 24,397,000 |  |  |  |  |
Debt securities |  | 271,865,000 |  |  |  |  |
Loans receivable |  | 627,767,000 |  |  |  |  |
Core deposit intangible | [1] | 31,053,000 |  |  |  |  |
Accrued income and other assets |  | 78,274,000 |  |  |  |  |
Total identifiable assets acquired |  | 1,033,356,000 |  |  |  |  |
Liabilities assumed |  |  |  |  |  |  |
Deposits |  | 877,586,000 |  |  |  |  |
Borrowings | [2] | 36,880,000 |  |  |  |  |
Accrued expenses and other liabilities |  | 14,175,000 |  |  |  |  |
Total liabilities assumed |  | 928,641,000 |  |  |  |  |
Total identifiable net assets |  | 104,715,000 |  |  |  |  |
Goodwill recognized |  | $ 76,328,000 |  |  |  |  |
Core Deposit Intangible, Weighted Average Useful Life |  | 10 years |  |  |  |  |
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Subordinated Debentures |  | $ 7,903,000 |  |  |  |  |
Collegiate Peaks Bank |  |  |  |  |  |  |
Fair value of consideration transferred |  |  |  |  |  |  |
Fair value of Company shares issued, net of equity issuance costs |  |  | $ 69,764,000 |  |  |  |
Cash consideration for outstanding shares |  |  | 16,265,000 |  |  |  |
Effective settlement of pre-existing receivable |  |  | 10,054,000 |  |  |  |
Total fair value of consideration transferred |  |  | 96,083,000 |  |  |  |
Identifiable assets acquired |  |  |  |  |  |  |
Cash and cash equivalents |  |  | 93,136,000 |  |  |  |
Debt securities |  |  | 42,177,000 |  |  |  |
Loans receivable |  |  | 354,252,000 |  |  |  |
Core deposit intangible | [1] |  | 10,275,000 |  |  |  |
Accrued income and other assets |  |  | 15,911,000 |  |  |  |
Total identifiable assets acquired |  |  | 515,751,000 |  |  |  |
Liabilities assumed |  |  |  |  |  |  |
Deposits |  |  | 437,171,000 |  |  |  |
Borrowings |  |  | 12,509,000 |  |  |  |
Accrued expenses and other liabilities |  |  | 5,435,000 |  |  |  |
Total liabilities assumed |  |  | 455,115,000 |  |  |  |
Total identifiable net assets |  |  | 60,636,000 |  |  |  |
Goodwill recognized |  |  | $ 35,447,000 |  |  |  |
Core Deposit Intangible, Weighted Average Useful Life |  |  | 10 years |  |  |  |
The Foothills Bank |  |  |  |  |  |  |
Fair value of consideration transferred |  |  |  |  |  |  |
Fair value of Company shares issued, net of equity issuance costs |  |  |  | $ 46,673,000 |  |  |
Cash consideration for outstanding shares |  |  |  | 17,342,000 |  |  |
Effective settlement of pre-existing receivable |  |  |  | 0 |  |  |
Total fair value of consideration transferred |  |  |  | 64,015,000 |  |  |
Identifiable assets acquired |  |  |  |  |  |  |
Cash and cash equivalents |  |  |  | 13,251,000 |  |  |
Debt securities |  |  |  | 25,420,000 |  |  |
Loans receivable |  |  |  | 292,529,000 |  |  |
Core deposit intangible | [1] |  |  | 4,331,000 |  |  |
Accrued income and other assets |  |  |  | 19,699,000 |  |  |
Total identifiable assets acquired |  |  |  | 355,230,000 |  |  |
Liabilities assumed |  |  |  |  |  |  |
Deposits |  |  |  | 296,760,000 |  |  |
Borrowings |  |  |  | 22,800,000 |  |  |
Accrued expenses and other liabilities |  |  |  | 2,264,000 |  |  |
Total liabilities assumed |  |  |  | 321,824,000 |  |  |
Total identifiable net assets |  |  |  | 33,406,000 |  |  |
Goodwill recognized |  |  |  | $ 30,609,000 |  |  |
Core Deposit Intangible, Weighted Average Useful Life |  |  |  | 10 years |  |  |
[1] | The core deposit intangible for each acquisition was determined to have an estimated life of 10 years.
[2] | Borrowings assumed with the FSB acquisition include Tier 2 subordinated debentures of $7,903,000.

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