Stock Incentive Plans - Summary of Assumptions Used for Valuation of Equity Instruments Granted (Detail) (USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member] Minimum [Member]	Sep. 30, 2013 Restricted Stock [Member] Maximum [Member]
Restricted stock:
Risk free rate, Maximum			0.18%	0.21%
Risk free rate, Minimum			0.03%	0.18%
Quarterly dividend per share	$ 0.05	$ 0.15		$ 0.05
Expected annual forfeiture rate				9.00%	0.00%	9.00%

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Based payment award fair value assumptions expected forfeiture rate.

+ References

No definition available.

+ Details

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- Definition

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

+ 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 S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

No definition available.

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- Definition

The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

No definition available.

+ Details

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