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Stockholders' Equity and Stock Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2019 | Apr. 01, 2018 | Mar. 31, 2019 | Apr. 01, 2018
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Stock-based compensation expense | $ 4.1 | $ 4.7 | $ 8.6 | $ 8.7
Performance-based restricted stock |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Percentage of shares that ultimately vest depending on growth in diluted earnings per share |  |  | 50.00% |
Percentage of shares that ultimately vest depending on the shareholder return relative to peer group of companies over vesting period |  |  | 50.00% |
Performance-based restricted stock | Non-employee directors and executive officers |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Granted (in shares) |  |  | 89,816 |
Granted, fair value (in dollars per share) |  |  | $ 80.41 |
Vesting period |  |  | 3 years |
Restricted stock units | Non-employee directors, executive officers and employees |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Granted (in shares) |  |  | 176,491 |
Granted, fair value (in dollars per share) |  |  | $ 66.11 |
Restricted stock units | Executive officers and employees |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Vesting period |  |  | 4 years |
Restricted stock units | Non-employee director |  |  |  |
Stockholders' Equity and Stock Compensation Plans |  |  |  |
Vesting period |  |  | 1 year |

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- Definition Represents the percentage of performance-based shares that ultimately vests, depending upon the fiscal year shareholder return relative to peer group of companies over the vesting period of the reporting entity. + 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -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=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -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=109197908&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://fasb.org/us-gaap/role/ref/legacyRef -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=109197908&loc=d3e5070-113901 + Details
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