Aggregate dividends declared during the period for each share of common stock outstanding.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in 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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Amount of stock repurchase plan authorized.

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Amount remaining of a stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Total cost of shares repurchased divided by the total number of shares repurchased.

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Common Stock and Stock-Based Awards Plans - Dividends and Share Repurchase Authorization (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions					3 Months Ended		6 Months Ended
	Jun. 15, 2021	Mar. 15, 2021	Jun. 15, 2020	Mar. 16, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Feb. 20, 2019	Oct. 26, 2018	Mar. 06, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends paid					$ 5,900,000	$ 5,800,000	$ 11,600,000	$ 11,400,000
Quarterly cash dividend declared	$ 0.165	$ 0.16	$ 0.16	$ 0.16
Repurchase of common shares program authorized amount									$ 150,000,000	$ 100,000,000	$ 250,000,000
Repurchase of common shares remaining authorized amount					$ 173,900,000		$ 173,900,000
Accelerated Stock Repurchase Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of common Shares					0.6		1.0
Repurchase of common shares, value					$ 17,300,000		$ 30,300,000
Repurchase of common shares, average cost per share					$ 30.48		$ 30.06