Annual report pursuant to section 13 and 15(d)

Per Share Data - Additional Information (Detail)

v2.4.0.6
Per Share Data - Additional Information (Detail)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Anti-dilutive securities excluded from computation of earnings per share amount 54,837,515 13,337,994 30,012,740