Share-based payments. During the three years ended December 31, 2017, the Company granted executives and senior management shares of restricted common stock which are time-based. Prior to 2016, time-based restricted common stock grants vested at the end of three years after the grant date. The time-based grants in 2016 and future periods vest equally on each of the first three anniversaries of the grant date. The Company also granted performance-based shares of restricted common stock which vest upon achievement of certain financial objectives over a period of three years. The aggregate grant-date fair values of restricted common stock awards in 2017, 2016 and 2015 were $5.7 million (133,000 shares with an average grant price of $42.59), $4.1 million (110,000 shares with an average grant price of $37.34) and $4.4 million (119,000 shares with an average grant price of $37.16), respectively. Awards were made pursuant to the Company’s employee incentive compensation plans and the compensation expense associated with restricted stock awards is recognized over the corresponding vesting period as part of employee costs in the consolidated statements of operations. Award forfeitures are recorded as credits against employee costs in the period in which they occur.

Additionally, in 2017, 2016 and 2015, the Company granted its board of directors, as a component of their annual director retainer compensation, approximately 13,000, 18,000 and 18,000 shares, respectively, of common stock, which immediately vested at grant date. The aggregate fair values of these director awards at grant dates were $0.6 million, $0.6 million and $0.7 million, respectively, and the associated expense is recognized in other operating expenses in the consolidated statements of operations.

A summary of the restricted common stock award activity during the year ended December 31, 2017 is presented below:



	Shares		Weighted-Average Grant-Date Fair Value per Share ($)

Nonvested balance at January 1, 2017	206,327		37.18
Granted	132,957		42.59
Adjustment for performance-based shares	(59,348	)	42.78
Vested	(59,260	)	36.98
Forfeited	(76,712	)	37.28
Nonvested balance at December 31, 2017	143,964		39.89

The fair value of shares that vested in 2017 and 2016 aggregated to $2.5 million and $3.8 million, respectively. For the years ended December 31, 2017, 2016 and 2015, compensation costs recognized in the statements of operations, presented within employee costs, were approximately $5.3 million, $3.0 million and $4.4 million, respectively. The total tax benefits recognized in the statement of operations from tax deductions relating to vesting of restricted common stock awards in 2017, 2016 and 2015 were $1.2 million, $1.7 million and $1.0 million, respectively. As of December 31, 2017, compensation costs not yet recognized related to nonvested restricted common stock awards was $5.1 million, which is expected to be recognized over a weighted average period of 1.5 years.