Share-based payments. Prior to 2018, the Company granted executives and senior management shares of restricted common stock, consisting of time-based shares, which vest on each of the first three anniversaries of the grant date, and performance-based shares, which vest upon achievement of certain financial objectives over the period of three years. Starting on January 1, 2018, the Company began granting time-based and performance-based restricted stock units, which have vesting conditions generally similar to the restricted common stock shares awarded previously. Each restricted stock unit represents a contractual right to receive a share of the Company's common stock.

The aggregate grant-date fair values of restricted share and unit awards during 2018, 2017 and 2016 were $4.8 million (110,600 shares with an average grant price of $43.39), $5.7 million (133,000 shares with an average grant price of $42.59) and $4.1 million (110,000 shares with an average grant price of $37.34), respectively. Awards were made pursuant to the Company’s employee incentive compensation plans and the compensation expense associated with the restricted share-based awards is recognized over the corresponding vesting period as part of employee costs in the consolidated statements of income. Award forfeitures are recorded as credits against employee costs in the period in which they occur.

Additionally, in 2018, 2017 and 2016, the Company granted its board of directors, as a component of their annual director retainer compensation, approximately 14,300, 13,000 and 18,000 shares, respectively, of common stock, which immediately vested at grant date and had aggregate fair values of $0.6 million each year. The associated expense is recognized in other operating expenses in the consolidated statements of income.

A summary of the restricted common stock award activity during the year ended December 31, 2018 is presented below:



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

Nonvested balance at January 1, 2018	143,964		39.89
Adjustment for performance-based shares	94,851		39.41
Vested	(100,479	)	38.27
Forfeited	(18,060	)	39.04
Nonvested balance at December 31, 2018	120,276		40.99

A summary of the restricted common stock unit activity during the year ended December 31, 2018 is presented below:



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

Nonvested balance at January 1, 2018	19,664		38.14
Granted	110,564		43.39
Vested	(2,975	)	38.64
Forfeited	(3,412	)	43.59
Nonvested balance at December 31, 2018	123,841		42.67

The fair value of shares that vested in 2018 and 2017 aggregated to $4.2 million and $2.5 million, respectively. For the years ended December 31, 2018, 2017 and 2016, compensation costs recognized in the statements of income, presented primarily within employee costs, were approximately $4.8 million, $5.3 million and $3.0 million, respectively. The total tax benefits recognized in the statement of income from tax deductions relating to vesting of restricted common stock awards in 2018, 2017 and 2016 were $1.1 million, $1.2 million and $1.7 million, respectively. As of December 31, 2018, compensation costs not yet recognized related to nonvested restricted common stock awards was $4.4 million, which is expected to be recognized over a weighted average period of 1.6 years.