The Company has authorized common stock of 200,000,000 shares, par value $0.00001 per share. In June 2018 the Company amended its certificate of incorporation to increase the total number of authorized shares of common stock from 100,000,000 shares to 200,000,000 shares.

In November 2018, the Company’s Board of Directors authorized a $150 million common stock repurchase program (the “Share Repurchase Program”) pursuant to which the Company may, from time to time, repurchase shares of common stock on the open market (either with or without a 10b5-1 plan) or through privately negotiated transactions. The Share Repurchase Program has no time limit and may be suspended or discontinued at any time without notice. There is no minimum number of shares of common stock that the Company is required to repurchase under the Share Repurchase Program.

The Company acquired 223,823 shares of common stock at an aggregate value of $9.1 million and an average of $40.80 per share during the year ended December 31, 2018. No shares were repurchased during the three months ended March 31, 2019.

The Company accounts for stock-based compensation in accordance with ASC 718, Compensation—Stock Compensation. Total stock-based compensation expense in the accompanying Consolidated Statements of Income totaled $4.9 million and $3.7 million during the three months ended March 31, 2019 and 2018, respectively. These amounts are included in corporate expenses and, in the case of certain property positions, general and administrative expenses in the Company’s Consolidated Statements of Income. We recognized a reduction in income tax expense of $2.6 million and $3.4 million for the three months ended March 31, 2019 and 2018, respectively, for excess tax benefits related to stock-based compensation.

A summary of the restricted stock unit (RSU) activity for the three months ended March 31, 2019 is presented in the following table:

	Restricted Stock Units
	Units				Weighted- Average Grant Date Fair Value
					(in millions)
Unvested outstanding as of December 31, 2018		1,283,372		$		23.93
Granted (1)		352,869
Vested		(352,584	)
Unvested outstanding as of March 31, 2019		1,283,657		$		32.19

(1)

Included are 30,135 RSUs granted to non-employee members of the Board of Directors during the three months ended March 31, 2019.

As of March 31, 2019 and 2018, the Company had $28.6 million and $16.6 million, respectively, of unrecognized compensation expense. The RSUs are expected to be recognized over a weighted-average period of 1.90 years and 1.58 years, respectively.

There was no ERI stock option activity for the three months ended March 31, 2019. Outstanding options as of March 31, 2019 totaled 135,956, of which 119,505 options were exercisable.