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Compensation Plans: Stock Based (Details) $ / shares in Units, $ in Millions | 12 Months Ended
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Dec. 31, 2015 USD ($) shares $ / shares | Dec. 31, 2014 USD ($) $ / shares shares | Dec. 31, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Number of shares available for grant |  | 2,800,000 |  |
Impact outright issuance of one share has on number of available shares |  | 1 |  |
Director Shares |  |  |  |
Minimum Service Requirement for Immediate Vesting of Granted Shares |  | 5 years |  |
Shares Issued to the Board of Directors [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Award Vesting Period |  | 1 year |  |
Stock-based compensation expense | $ |  | $ 1.6 | $ 1.6 | $ 1.4
Director Shares |  |  |  |
Stock Issued During Period, Shares, Share-based Compensation, Gross |  | 37,950 | 27,677 | 28,169
Shares Issued to Former CEO for Service As Director [Member] |  |  |  |
Director Shares |  |  |  |
Stock Issued During Period, Shares, Share-based Compensation, Gross |  | 1,953 |  |
Performance Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Maximum Impact of issuance of one performance share award on available shares under the equity incentive plan |  | 2 |  |
Multiplier Applied to PSU Awards at Settlement |  | 1.0 | 0.55 | 1.725
Award Vesting Period |  | 3 years |  |
Stock-based compensation expense | $ |  | $ 10.6 | $ 16.0 | $ 16.8
Unrecognized stock based compensation expense | $ |  | 18.4 |  |
Fair value of PSUs/RSUs Granted in Period | $ |  | $ 14.5 | 19.2 | 17.6
Multiplier assumed |  | 1 |  |
Fair value of PSUs/RSUs Vested in Period | $ |  | $ 4.0 | $ 13.4 | $ 20.7
Shares Issued in Period |  | 188,279 | 85,121 | 387,461
Shares held for settlement of income and payroll tax obligations (in shares) |  | 100,683 | 45,042 | 200,050
Weighted Average Grant Date Fair Value |  |  |  |
Non-vested at beginning of year (in shares) | [1] | 433,660 | 572,469 | 669,308
Granted (in shares) | [1] | 320,753 | 202,404 | 274,831
Vested (in shares) | [1] | (76,438) | (206,830) | (345,005)
Forfeited (in shares) | [1] | (51,647) | (134,383) | (26,665)
Non-vested at end of year (in shares) | [1] | 626,328 | 433,660 | 572,469
Non-vested outstanding at the beginning of the period (in dollars per share) | $ / shares | [1] | $ 73.63 | $ 66.07 | $ 63.91
Granted (in dollars per share) | $ / shares | [1] | 45.34 | 94.66 | 64.13
Vested (in dollars per share) | $ / shares | [1] | 51.76 | 64.79 | 60.06
Forfeited (in dollars per share) | $ / shares | [1] | 73.62 | 86.72 | 69.74
Non-vested outstanding at the end of the period (in dollars per share) | $ / shares | [1] | $ 61.81 | $ 73.63 | $ 66.07
Restricted Stock Units (RSUs) [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Award Vesting Period |  | 3 years |  |
Stock-based compensation expense | $ |  | $ 13.4 | $ 13.9 | $ 13.1
Unrecognized stock based compensation expense | $ |  | 19.3 |  |
Fair value of PSUs/RSUs Granted in Period | $ |  | $ 15.6 | $ 19.7 | $ 19.8
PSU/RSU Vesting Increment |  | 0.33 | 0.33 | 0.33
Fair value of PSUs/RSUs Vested in Period | $ |  | $ 17.6 | $ 14.7 | $ 10.3
Restricted Stock, Shares Settled Gross of Shares for Tax Withholdings |  | 278,289 | 253,031 | 207,378
Shares held for settlement of income and payroll tax obligations (in shares) |  | 91,045 | 81,434 | 67,987
Number of Shares Represented by Each RSU |  | 1 |  |
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings |  | 187,244 | 171,597 | 139,391
Weighted Average Grant Date Fair Value |  |  |  |
Non-vested at beginning of year (in shares) |  | 515,724 | 580,431 | 496,244
Granted (in shares) |  | 356,246 | 234,560 | 329,939
Vested (in shares) |  | (278,289) | (253,031) | (207,376)
Forfeited (in shares) |  | (49,944) | (46,236) | (38,376)
Non-vested at end of year (in shares) |  | 543,737 | 515,724 | 580,431
Non-vested outstanding at the beginning of the period (in dollars per share) | $ / shares |  | $ 68.29 | $ 57.05 | $ 51.81
Granted (in dollars per share) | $ / shares |  | 43.72 | 83.98 | 60.01
Vested (in dollars per share) | $ / shares |  | 63.12 | 58.19 | 49.73
Forfeited (in dollars per share) | $ / shares |  | 66.53 | 62.06 | 54.37
Non-vested outstanding at the end of the period (in dollars per share) | $ / shares |  | $ 55.01 | $ 68.29 | $ 57.05
Minimum [Member] | Performance Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Multiplier Applied to PSU Awards at Settlement |  | 0 |  |
Maximum [Member] | Performance Shares [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Multiplier Applied to PSU Awards at Settlement |  | 2 |  |
[1] | The number of awards assumes a multiplier of one. The final number of shares of common stock issued may vary depending on the three-year performance multiplier, which ranges from zero to two.

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- Definition Maximum Number of Shares Granted for Each Performance Share + References No definition available. + Details
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- Definition Multiplier Applied to PSU Awards at Settlement + References No definition available. + Details
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- Definition The number of restricted shares settled as compensation, gross of shares for the payment of withholding taxes. This element is to be used only if shares are used in lieu of cash to satisfy all or a portion of withholding taxes. + References No definition available. + Details
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- Definition Represents the multiplier assumed for performance based awards which the grantee gained the right to during the reporting period, by satisfying service requirements. + References No definition available. + Details
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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- Definition Unrecognized cost of unvested share-based compensation awards. + 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 (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of restricted shares issued as compensation, net of shares for the payment of withholding taxes. This element is to be used only if shares are used in lieu of cash to satisfy all or a portion of withholding taxes. + References No definition available. + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + 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)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. + 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)(2)(iii)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + 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)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + 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)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + 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)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. + 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)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + 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)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. + 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)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Number of share instruments newly issued under a share-based compensation plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer. + References No definition available. + Details
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- Definition Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. + References No definition available. + Details
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