8. Equity

Common Stock

As of June 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 six months ended June 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					Six Months Ended
	June 30, 2017					June 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)	20,794	$	9.4			162,302	$	14.2
Stock options exercised	1,225		—	$	55.73	56,530		2.8	$	49.95
Total	22,019	$	9.4			218,832	$	17.0

⁽¹⁾

The six months ended June 30, 2017 amount is comprised of stock-based compensation expense of $14.9 million reduced by $0.7 million of payments we made to tax authorities on our employees’ behalf for shares withheld related to net share settlements.

Dividends

On July 25, 2017, our Board of Directors declared the 2017 third quarter cash dividend of $0.45 per share. The dividend is payable on September 8, 2017 to stockholders of record as of August 18, 2017.

During the second quarters of 2017 and 2016, we declared and paid quarterly dividends of $0.45 per share and $0.40 per share, or $32.8 million and $29.0 million in total, respectively. During the six months ended June 30, 2017 and 2016, we declared and paid quarterly dividends of $0.90 and $0.80 per share, or $65.6 million and $57.1 million in total, respectively. During the six months ended June 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. During the three months ended June 30, 2017, we granted 18,120 shares of restricted stock to the non-employee members of the Board of Directors with a fair value of $71.73 per share. 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 June 30, 2017 and changes during the six-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	(6,029)		61.86
Cancelled	(31,901)		67.40
Unvested at June 30, 2017	1,394,135	$	69.17
Shares reserved for future grants (all plans)	1,643,169

⁽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		14.0		2.3		16.3
Balance as of June 30, 2017	$	(65.9)	$	(22.5)	$	(88.4)

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 June 30, 2017 and December 31, 2016, respectively.