Earnings Per Share - Reconciliation of Shares Used in Basic and Diluted EPS Calculations (Details) 1
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Weighted average number of shares used in computing basic EPS 207,641,523 206,525,188
Add dilutive common stock equivalents:    
Outstanding stock options and restricted stock units 648,166 [1] 561,489 [1]
Weighted average number of shares used in computing diluted EPS 208,289,689 207,086,677
Anti-dilutive Stock Options and RSU [Member]    
Add dilutive common stock equivalents:    
Antidilutive securities excluded from computation of earnings per share, amount 1,486,626 1,389,283
[1] Excludes 1,486,626 and 1,389,283 common stock equivalents for the three months ended March 31, 2015 and 2014 because their effect was anti-dilutive.