Value of shares of common stock repurchased under the stock repurchase program over the life of the plan to date.

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Number of shares of common stock repurchased under the stock repurchase program over the life of the plan to date.

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No definition available.

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- Definition

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

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

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Face amount or stated value per share of common stock.

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Date the declared dividend will be paid, in CCYY-MM-DD format.

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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The month and year (YYYY-MM) that the dividend to be paid was declared.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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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 an established share-based compensation plan.

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Amount of stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended				6 Months Ended
	Jul. 31, 2018	May 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Feb. 28, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value			$ 0.01				$ 0.01			$ 0.01
Dividend declared and paid per share			0.20	$ 0.20	$ 0.19	$ 0.19
Aggregate dividend declared for the year							$ 7,200,000	$ 6,800,000
Dividend declared per share			$ 0.20		$ 0.19		$ 0.40	$ 0.38
Authorized to purchase of common stock under the stock repurchase program			$ 535,000,000				$ 535,000,000		$ 50,000,000
Repurchase of common Stock			100,000		400,000		200,000	1,000,000
Cumulative aggregate cost of repurchase of common stock			$ 5,300,000		$ 15,000,000		$ 9,600,000	$ 36,500,000
Cumulative repurchase of common stock			16,300,000				16,300,000
Aggregate cost of repurchase of common stock							$ 474,600,000
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend declared per share	$ 0.20
Dividend payable, date declared	2018-07
Dividend declared payable date	Sep. 26, 2018
Dividend payable, record date	Sep. 12, 2018
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares to be granted		400,000
Common stock, par value		$ 0.01