Share-Based Compensation	9 Months Ended
Sep. 30, 2019
Share-Based Compensation [Abstract]
Share-Based Compensation	(12) Share-Based Compensation As of September 30, 2019, there were 1,368,243 shares of common stock available for grant under the Tutor Perini Corporation Omnibus Incentive Plan. During the first nine months of 2019 and 2018, the Company issued the following share-based instruments: (1) restricted stock units totaling 400,000 and 614,000 with weighted-average fair values per share of $20.90 and $25.19, respectively; (2) stock options totaling 135,000 and 579,000 with weighted-average fair values per share of $6.84 and $11.45, respectively, and weighted-average per share exercise prices of $20.94 and $23.99, respectively; and (3) unrestricted stock units totaling 98,591 and 115,420 with weighted-average fair values per share of $15.72 and $21.26, respectively. During the nine months ended September 30, 2019, 839,711 stock options with a weighted-average per share exercise price of $20.78 expired or were forfeited. The fair value of restricted and unrestricted stock units is based on the closing price of the Company’s common stock on the New York Stock Exchange on the date of the grant and the fair value of stock options is based on the Black-Scholes model. The fair value of stock options granted during the first nine months of 2019 was determined using the Black-Scholes model based on the following weighted-average assumptions: (i) expected life of 5.8 years, (ii) expected volatility of 38.17%, (iii) risk-free rate of 2.31%, and (iv) no quarterly dividends. For certain performance-based awards containing market condition components, the fair value on the grant date is determined using a Monte Carlo simulation model. For the three and nine months ended September 30, 2019, the Company recognized, as part of general and administrative expenses, costs for share-based payment arrangements totaling $4.3 million and $14.3 million, respectively, and $5.7 million and $17.8 million for the three and nine months ended September 30, 2018, respectively. As of September 30, 2019, the balance of unamortized share-based compensation expense was $22.8 million, which is expected to be recognized over a weighted-average period of 2.1 years.

Share-Based Compensation

9 Months Ended

Sep. 30, 2019

(12) Share-Based Compensation

As of September 30, 2019, there were 1,368,243 shares of common stock available for grant under the Tutor Perini Corporation Omnibus Incentive Plan. During the first nine months of 2019 and 2018, the Company issued the following share-based instruments: (1) restricted stock units totaling 400,000 and 614,000 with weighted-average fair values per share of $20.90 and $25.19, respectively; (2) stock options totaling 135,000 and 579,000 with weighted-average fair values per share of $6.84 and $11.45, respectively, and weighted-average per share exercise prices of $20.94 and $23.99, respectively; and (3) unrestricted stock units totaling 98,591 and 115,420 with weighted-average fair values per share of $15.72 and $21.26, respectively. During the nine months ended September 30, 2019, 839,711 stock options with a weighted-average per share exercise price of $20.78 expired or were forfeited.

The fair value of restricted and unrestricted stock units is based on the closing price of the Company’s common stock on the New York Stock Exchange on the date of the grant and the fair value of stock options is based on the Black-Scholes model. The fair value of stock options granted during the first nine months of 2019 was determined using the Black-Scholes model based on the following weighted-average assumptions: (i) expected life of 5.8 years, (ii) expected volatility of 38.17%, (iii) risk-free rate of 2.31%, and (iv) no quarterly dividends. For certain performance-based awards containing market condition components, the fair value on the grant date is determined using a Monte Carlo simulation model.

For the three and nine months ended September 30, 2019, the Company recognized, as part of general and administrative expenses, costs for share-based payment arrangements totaling $4.3 million and $14.3 million, respectively, and $5.7 million and $17.8 million for the three and nine months ended September 30, 2018, respectively. As of September 30, 2019, the balance of unamortized share-based compensation expense was $22.8 million, which is expected to be recognized over a weighted-average period of 2.1 years.