Share-based compensation

6 Months Ended

Jun. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-based compensation

8. Share-based compensation

All share-based compensation costs are measured at the grant date, based on the estimated fair value of the award, and recognized as expense in the condensed consolidated statements of operations over the requisite service period. The Company recognized $1.9 million and $3.9 million, respectively, of share-based compensation expense for the three and six months ended June 30, 2016 and $1.8 million and $3.6 million, respectively, for the three and six months ended June 30, 2015.

On June 30, 2014, the Company granted 99,600 performance-based restricted share awards to officers and certain employees. Vesting is based on achieving earnings targets in two consecutive rolling four quarter periods. As of June 30, 2016, no expense has been recognized for these contingent restricted share awards.

On June 30, 2015, the Company granted 68,750 performance-based restricted share awards to officers and on August 5, 2015, granted an additional 41,910 performance-based restricted share awards to other members of management.  Vesting is based on achieving earnings and return on invested capital targets as of and for the years ended December 31, 2016, 2017 or 2018.  As of June 30, 2016, no expense has been recognized for these contingent restricted share awards.

During the three months ended June 30, 2016 and 2015, there were 325,393 and 81,974 shares, respectively, of common stock issued related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards. During the six months ended June 30, 2016 and 2015, there were 528,791 and 227,840 shares, respectively, of common stock issued related to stock purchase plan issuances, stock option exercises and the vesting of restricted stock awards.