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Capital Stock and Dividend Restrictions (Details) $ / shares in Units, $ in Thousands |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
May 30, 2017 USD ($) shares | Dec. 31, 2017 USD ($) votes shares | Dec. 31, 2016 USD ($) $ / shares shares | Dec. 31, 2015 USD ($) | Sep. 25, 2017 USD ($) | Jan. 26, 2017 shares
Class of Stock |  |  |  |  |  |
Common stock, shares authorized |  | 200,000,000 |  |  |  |
Aggregate purchase price of shares repurchased and retired | $ |  | $ 1,348 | $ 26,854 | $ 20,647 |  |
Common stock issued (in shares) | 11,300,000 |  |  |  |  |
Class A Common Stock |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Common stock, shares authorized |  | 100,000,000 |  |  |  |
Common stock, voting rights per share (vote per share) | votes |  | 1 |  |  |  |
Common stock, shares, outstanding |  | 33,560,202 | 21,613,885 |  |  |
Common shares purchased and retired |  | 0 | 975,877 |  |  |
Aggregate purchase price of shares repurchased and retired | $ |  |  | $ 25,500 |  |  |
Weighted average price of shares repurchased and retired (in dollars per share) | $ / shares |  |  | $ 26.16 |  |  |
Class B Common Stock |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Common stock, shares authorized |  | 100,000,000 |  |  |  |
Common stock, voting rights per share (vote per share) | votes |  | 5 |  |  |  |
Common stock, shares, outstanding |  | 22,905,357 | 23,312,291 |  |  |
Cascade Bank | Class A Common Stock |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Common stock, shares authorized |  |  |  |  |  | 11,839,179
Common stock issued (in shares) | 11,252,750 |  |  |  |  |
Class A common stock | $ | $ 386,000 |  |  |  |  |
Board of Directors |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Aggregate value of shares issued to directors | $ |  | $ 500 | $ 500 |  |  |
Board of Directors | Class A Common Stock |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Shares issued to directors during period |  | 14,926 | 16,347 |  |  |
Secondary Public Offering | Class A Common Stock |  |  |  |  |  |
Class of Stock |  |  |  |  |  |
Common stock, value authorized | $ |  |  |  |  | $ 250,000 |

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