8. Equity

Common Stock

As of September 30, 2017, we had authorization to purchase a total of approximately 8.4 million shares under our existing share repurchase plan, or about 12% of outstanding shares. There were no share repurchases in the nine months ended September 30, 2017. Repurchased and subsequently retired shares are restored to the status of authorized but unissued shares.

Common stock and additional paid-in capital activity included the following:


	Three Months Ended					Nine Months Ended
	September 30, 2017					September 30, 2017
				Weighted Average					Weighted Average
	Shares	Amount		Exercise Price		Shares	Amount		Exercise Price
	(in millions, except share and per share amounts)
Stock-based compensation(1)	2,133	$	8.4			164,435	$	22.5
Stock options exercised	9,925		0.5	$	55.73	66,455		3.4	$	50.81
Total	12,058	$	8.9			230,890	$	25.9

⁽¹⁾

The nine months ended September 30, 2017 amount is comprised of stock-based compensation expense of $23.3 million reduced by $0.8 million of payments we made to tax authorities on our employees’ behalf for shares withheld related to net share settlements.

Dividends

On October 24, 2017, our Board of Directors declared the 2017 fourth quarter cash dividend of $0.45 per share. The dividend is payable on December 8, 2017 to stockholders of record as of November 17, 2017.

During the third quarters of 2017 and 2016, we declared and paid quarterly dividends of $0.45 and $0.425 per share, or $32.8 million and $31.5 million in total, respectively. During the nine months ended September 30, 2017 and 2016, we declared and paid quarterly dividends of $1.35 and $1.225 per share, or $98.4 million and $88.6 million in total, respectively. During the nine months ended September 30, 2017 and 2016, we paid $0.9 million in dividend equivalents with respect to vested restricted stock units (“RSUs”).

Stock-Based Compensation

We make annual grants of long-term incentive awards to officers and key employees in the forms of service-based and performance-based RSUs that generally have 3-year vesting periods. The performance-based RSU awards are subject to both service and performance goal criteria. We also make annual grants of restricted stock to the non-employee members of the Board of Directors that include dividend rights and vest immediately upon grant. The fair value of the RSUs and restricted stock awards is determined based on the closing stock price of our common stock on the grant date.

A summary of the status of our unvested service-based and performance-based RSUs as of September 30, 2017 and changes during the nine-month period then ended is as follows:


		Weighted
		Average Grant
Unvested Shares	Shares	Date Fair Value
Unvested at January 1, 2017	985,540	$	64.34
Granted(1)	446,525		79.60
Vested	(8,159)		62.49
Cancelled	(38,274)		67.84
Unvested at September 30, 2017	1,385,632	$	69.18
Shares reserved for future grants (all plans)	1,650,458

⁽¹⁾

446,525 RSUs, including 169,009 performance-based RSUs.

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss included the following:


			Pension and		Accumulated
	Foreign Currency		Postretirement		Other
	Translation		Benefit Adjustments,		Comprehensive
	(Loss) Gain		Net of Tax		(Loss) Income
	(in millions)
Balance as of January 1, 2017	$	(79.9)	$	(24.8)	$	(104.7)
Current-period change		24.5		2.3		26.8
Balance as of September 30, 2017	$	(55.4)	$	(22.5)	$	(77.9)

Foreign currency translation adjustments are not generally adjusted for income taxes as they relate to indefinite investments in foreign subsidiaries. Pension and postretirement benefit adjustments are net of taxes of $13.5 million and $14.9 million as of September 30, 2017 and December 31, 2016, respectively.