Unaudited Pro Forma Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pro forma earnings per share (unaudited):
Basic	$ 0.59	$ 0.57	$ 0.89	$ 1.01
Diluted	$ 0.58	$ 0.56	$ 0.87	$ 1.00

Pro forma basic earnings per share or earnings per unit, which is commonly presented in initial public offerings based on the terms of the offering.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph b

-Subparagraph 7

-Article 11

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration