Number of Stock Options and Nonvested Share-Awards that were Issued or Outstanding but were Excluded in Calculating Diluted Earnings Per Share Because their Effect would have been Anti-Dilutive (Detail)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from the computation of dilutive EPS 1,108,000 641,000
Stock options    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Anti-dilutive securities excluded from the computation of dilutive EPS 1,108,000 641,000