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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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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 $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended			0 Months Ended
	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 20, 2015	Nov. 30, 2014	Apr. 30, 2014
Class of Stock [Line Items]
Common stock, shares authorized		90,000,000us-gaap_CommonStockSharesAuthorized	90,000,000us-gaap_CommonStockSharesAuthorized
Common stock, par value (usd per share)		$ 1	$ 1
Common stock, shares issued		64,200,000us-gaap_CommonStockSharesIssued	63,800,000us-gaap_CommonStockSharesIssued
Common stock, shares outstanding		62,500,000us-gaap_CommonStockSharesOutstanding	62,800,000us-gaap_CommonStockSharesOutstanding
Preference stock, shares authorized		800,000us-gaap_PreferredStockSharesAuthorized
Preference stock, par value (usd per share)		$ 1
Cash dividends declared per common share (usd per share)	$ 0.03	$ 0.09	$ 0.00	$ 0.00
Authorized amount						$ 75.0	$ 15.0
Shares acquired		696,263us-gaap_TreasuryStockSharesAcquired
Stock repurchase program, amount acquired		10.3
Cash dividends paid to stockholders		$ 5.6us-gaap_PaymentsOfDividendsCommonStock	$ 0us-gaap_PaymentsOfDividendsCommonStock	$ 0us-gaap_PaymentsOfDividendsCommonStock
Subsequent Event [Member]
Class of Stock [Line Items]
Cash dividends declared per common share (usd per share)					$ 0.06