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Acquisitions - Summary of Pre-tax Merger Related Costs (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Business Acquisition [Line Items] |  |
Employee Expenses | $ 34.6 | $ 25.7
Total Acquisition Related Expenses | 2.3 | 0.7
Bank of the Cascades |  |
Business Acquisition [Line Items] |  |
Legal and Professional Fees | 0.5 | 0.6
Employee Expenses | 0.1 | 0.0
Technology Conversion and Contract Termination | 1.5 | 0.0
Other | $ 0.2 | 0.1
Total Acquisition Related Expenses |  | $ 0.7

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460 + Details
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- Definition The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including equity-based compensation, and pension and other postretirement benefit expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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