Shareholders' Equity - Additional Information (Detail) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2014
Equity [Abstract]
Share repurchase program, authorized amount				$ 100,000,000
Stock repurchased and retired, shares	300	560
Stock repurchased and retired, value	(9,934,000)	(18,876,000)	(15,000,000)
Stock repurchase program, average price per share (dollars per share)	$ 34.31	$ 33.72
Remaining amount available under the program for the repurchase of shares	90,100,000
Payments to Acquire Additional Interest in Subsidiaries	$ 1,500,000	$ 0	$ 0

Stock repurchased and retired during period average cost.

No definition available.

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- Details

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- Definition

The cash outflow associated with the purchase of noncontrolling interest during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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- Definition

Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

+ Details

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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- Definition

Amount remaining of a stock repurchase plan authorized.

+ References

No definition available.

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