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Stock Based Compensation Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range (Details) | 12 Months Ended
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Dec. 31, 2017 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 346,155.000
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 5 years 1 month 10 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 24.12
Number of Shares Outstanding, Exercisable Options, in shares | shares | 225,694.000
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 3 years 6 months 15 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 21.61
Exercise Price Range $18.00 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 27,999
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 1 year 22 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 18.00
Number of Shares Outstanding, Exercisable Options, in shares | shares | 27,999
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 1 year 22 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 18.00
Exercise Price Range $20.17 to $21.56 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 85,068
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 2 years 6 months 29 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 20.98
Number of Shares Outstanding, Exercisable Options, in shares | shares | 85,068
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 2 years 6 months 29 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 20.98
Exercise Price Range $22.14 to $22.65 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 94,111
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 4 years 5 months 27 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 22.43
Number of Shares Outstanding, Exercisable Options, in shares | shares | 79,797
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 4 years 2 months 12 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 22.39
Exercise Price Range $23.89 to $24.37 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 89,536
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 7 years 3 months 7 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 24.15
Number of Shares Outstanding, Exercisable Options, in shares | shares | 31,800
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 6 years 5 months 27 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 24.08
Exercise Price Range $36.12 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Number of Shares Outstanding, Outstanding Options, in shares | shares | 49,441
Weighted-Average Remaining Contractual Life, Outstanding Options, in years | 9 years 26 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price | $ 36.12
Number of Shares Outstanding, Exercisable Options, in shares | shares | 1,030
Weighted-Average Remaining Contractual Life, Exercisable Options, in years | 9 years 26 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 36.12
Minimum [Member] | Exercise Price Range $20.17 to $21.56 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | 20.17
Minimum [Member] | Exercise Price Range $22.14 to $22.65 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | 22.14
Minimum [Member] | Exercise Price Range $23.89 to $24.37 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | 23.89
Maximum [Member] | Exercise Price Range $20.17 to $21.56 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | 21.56
Maximum [Member] | Exercise Price Range $22.14 to $22.65 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | 22.65
Maximum [Member] | Exercise Price Range $23.89 to $24.37 [Member] |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price | $ 24.37

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- Definition The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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