Stock Based Compensation

9 Months Ended

Sep. 30, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Based Compensation

Stock-Based Compensation

The Company’s 2003 Stock Incentive Plan, or the 2003 Plan, permits stock-based compensation awards to officers, directors, key employees and consultants. As of September 30, 2016, the 2003 Plan authorized grants of stock‑based compensation instruments to purchase or issue up to 19,686,565 shares of Company common stock, subject to adjustments provided by the 2003 Plan. As of September 30, 2016, there were 12,450,068 shares available for grant under the 2003 Plan.

Restricted stock amortization totaled $5.6 million, $6.0 million, and $3.8 million for the three months endedSeptember 30, 2016, June 30, 2016 and September 30, 2015 and, $16.6 million and $11.2 million for the nine months endedSeptember 30, 2016 and 2015. Such amounts are included in "Compensation expense" on the condensed consolidated statements of earnings. The amount of unrecognized compensation expense related to unvested time-based restricted stock awards ("TRSAs") and performance-based restricted stock units ("PRSUs") as of September 30, 2016 totaled $45.7 million.

Time-Based Restricted Stock Awards

At September 30, 2016, there were 1,397,715 shares of unvested TRSAs outstanding. The TRSAs generally vest over a service period of three or four years from the date of the grant or immediately upon the death of an employee. Compensation expense related to TRSAs is based on the fair value of the underlying stock on the award date and is recognized over the vesting period using the straight‑line method.

Performance-Based Restricted Stock Units

At September 30, 2016, there were 153,715 units of unvested PRSUs outstanding. The PRSUs will vest only if performance goals with respect to certain financial metrics are met over a three-year performance period. Compensation expense related to PRSUs is based on the fair value of the underlying stock on the award date and is amortized over the vesting period using the straight-line method unless it is determined that: (1) attainment of the financial metrics is less than probable, in which case a portion of the amortization is suspended, or (2) attainment of the financial metrics is improbable, in which case a portion of the previously recognized amortization is reversed and also suspended. In the case where the performance target for the PRSU’s is based on a market condition (such as total shareholder return), the amortization is neither reversed nor suspended if it is subsequently determined that the attainment of the performance target is less than probable or improbable.