It represents the expenses incurred and paid in connection with stock repurchase.

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+ References

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The cash outflow to reacquire common stock 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 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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Amount of stock repurchase plan authorized.

+ References

No definition available.

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- Definition

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

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Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
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-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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Capital Stock - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Feb. 04, 2016	Feb. 28, 2015
Class of Stock [Line Items]
Stock repurchase authorized amount			$ 250,000,000
Shares repurchased and retired (in shares)	1,356,199	590,713
Common stock shares repurchased price per share	$ 24.35	$ 22.51
Aggregate amount of common stock shares repurchased	$ 33,017,000	$ 13,298,000
Expenses related to stock purchases	$ 27,000	$ 12,000
February 2015 Stock Repurchase Program
Class of Stock [Line Items]
Stock repurchase authorized amount			$ 500,000,000
Maximum
Class of Stock [Line Items]
Stock repurchase authorized amount				$ 250,000,000