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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.

+ 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 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.

+ References

+ Details

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Period Type:	duration

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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Stock Repurchase Plans - Additional Information (Detail) (USD $)	3 Months Ended						12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 31, 2014	Nov. 30, 2012	Feb. 28, 2012
Equity, Class of Treasury Stock [Line Items]
Value of common stock authorized for repurchase										$ 2,000,000
Number of shares repurchased	3,900	22,811	88,445	9,800	59,006	214,087	183,962
Common stock repurchased, weighted-average price	$ 9.47	$ 9.45	$ 9.24	$ 5.87	$ 5.60	$ 4.67	$ 7.94
Common stock repurchased, value	37,000	216,000	817,000	58,000	332,000	1,000,000	1,070,000	58,000	1,332,000
Maximum
Equity, Class of Treasury Stock [Line Items]
Value of common stock authorized for repurchase											$ 2,000,000	$ 1,000,000