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Period over which plan activity is adjusted to determine the maximum number of shares that may be issued in accordance with the plan.

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Share-based Compensation Arrangement by Share-based Payment Award, Performance Measurement Period

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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).

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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).

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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.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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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.

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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.

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Number of additional shares authorized for issuance under share-based payment arrangement.

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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.

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Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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No definition available.

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Percentage of vesting of award under share-based payment arrangement.

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Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		12 Months Ended
	Feb. 11, 2020	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017	Mar. 31, 2019	Feb. 14, 2018	Feb. 15, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan activity adjustment period - Evergreen provision		5 years
Number of shares available for grant (in shares) - Fixed provision		3,400
Tax benefit		$ 1.3	$ 4.4	$ 4.2
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Unrecognized compensation cost, unvested restricted stock		$ 6.5
Compensation cost not yet recognized, period for recognition		1 year 9 months 18 days
Grants in period (in dollars per share)		$ 24.76	$ 28.79	$ 21.97
Vested in period, fair value		$ 3.3	$ 4.9	$ 5.8
Granted (in shares)		185
Weighted average grant date fair value (in dollars per share)		$ 24.92	$ 23.44
Total nonvested shares (in shares)		360	356
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		260	222	387
Performance measurement period		3 years	3 years	3 years
Performance Shares, Total Shareholder Return
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, unvested restricted stock		$ 0.5
Compensation cost not yet recognized, period for recognition		1 year
Grants in period (in dollars per share)		$ 0
Vested in period, fair value		$ 1.4
Granted (in shares)		0	59	101
Performance measurement period		3 years	3 years	3 years
Weighted average grant date fair value (in dollars per share)		$ 25.24	$ 23.56
Total nonvested shares (in shares)		114	173
Performance Shares, Total Shareholder Return \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual percentage achieved	0.00%
Performance Shares, Total Shareholder Return \| Monte Carlo Fair Value
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)						$ 31.38	$ 20.16
Performance Shares, Single Financial Goal
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years	4 years	4 years
Granted (in shares)		53	45	83
Performance measurement period		1 year	1 year	1 year
Performance Shares, Financial Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, unvested restricted stock		$ 1.0
Compensation cost not yet recognized, period for recognition		1 year 10 months 24 days
Vested in period, fair value		$ 3.4
Granted (in shares)			118	203
Weighted average grant date fair value (in dollars per share)		$ 25.54				$ 28.40	$ 21.07
Performance Shares, Financial Goals \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual percentage achieved	55.00%
Stock-based compensation cost
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation cost		$ 5.6	$ 8.1	$ 9.1
Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for grants - Evergreen provision		15.00%
Maximum number of shares available for grants - Fixed provision		4,700
Performance shares eligible to earn more than target \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		207	177	304
Maximum shares eligible to earn \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		413	355	609
Maximum target percentage allowed under grant		200.00%	200.00%	200.00%
Maximum shares eligible to earn \| Performance Shares, Financial Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum target percentage allowed under grant			200.00%
2019 grant \| Maximum shares eligible to earn \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total nonvested shares (in shares)		364
2018 grant \| Performance Shares, Total Shareholder Return
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total nonvested shares (in shares)		104
2018 grant \| Performance Shares, Financial Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)		$ 21.38
Total nonvested shares (in shares)		207
2017 grant \| Performance Shares, Total Shareholder Return
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total nonvested shares (in shares)		0
2017 grant \| Performance Shares, Financial Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)					$ 23.76
Total nonvested shares (in shares)		69