The Company considers its unvested share based payment awards, which contain non-forfeitable rights to dividends, participating securities, and includes such participating securities in its computation of earnings per share pursuant to the two-class method. Basic earnings per share for the two classes of stock (common stock and unvested restricted stock) is calculated by dividing net income by the weighted average number of shares of common stock and unvested restricted stock outstanding during the reporting period. Diluted earnings per share is calculated using the weighted average number of shares of common stock plus the potentially dilutive effect of common equivalent shares outstanding determined under both the two class method and the treasury stock method.

Effective January 1, 2017, the Company adopted ASU 2016-09 on a prospective basis. In accordance with the amendments in ASU 2016-09, the Company’s diluted earnings per share calculation for the year ended December 31, 2017 excludes the estimated income tax benefits and deficiencies in the application of the treasury stock method. Excess income tax benefits or deficiencies related to share based awards are recognized as discrete items in the income statement during the period in which they occur. See Note 15 for a discussion of share based awards and related income tax benefits recognized during the years ended December 31, 2016, 2017 and 2018.

The following table presents computations of basic and diluted earnings per share under the two class method: