EARNINGS PER SHARE

We apply the two-class method of computing earnings per share, which requires the calculation of separate earnings per share amounts for our non-vested time-based restricted stock awards with non-forfeitable dividends and for our common stock. Our non-vested time-based restricted stock awards with non-forfeitable rights to dividends are considered securities which participate in undistributed earnings with common stock. Under the two-class computation method, net losses are not allocated to participating securities unless the holder of the security has a contractual obligation to share in the losses. Our non-vested time-based restricted stock awards with non-forfeitable dividends do not have such an obligation so they are not allocated losses.

Below is a summary of the components used to calculate basic and diluted earnings per share (in thousands, except per share):



	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2018			2017			2018			2017
Numerator:
Net income	$	37,677		$	34,083		$	47,368		$	67,289
Less: Preferred dividends	(3,709		)	(4,200		)	(9,252		)	(8,400		)
Premium on redemption of preferred stock	—			—			(3,277		)	—
Allocation to participating securities	(120		)	(126		)	(137		)	(240		)
Attributable to non-controlling interest	(101		)	(114		)	(104		)	(234		)
Net income attributable to common stockholders, net of amount allocated to participating securities	$	33,747		$	29,643		$	34,598		$	58,415
Denominator:
Weighted average common shares outstanding - basic	103,643			98,184			103,572			95,488
Dilutive effect of equity-based compensation awards	240			522			320			495
Weighted average common shares outstanding - diluted	103,883			98,706			103,892			95,983
Earnings per share:
Basic	$	0.33		$	0.30		$	0.33		$	0.61
Diluted	$	0.32		$	0.30		$	0.33		$	0.61

All outstanding stock options were included in the computation of diluted earnings per share for the three and six months ended June 30, 2018 and 2017 due to their dilutive effect. The Common Units held by the non-controlling interest holders have been excluded from the denominator of the diluted earnings per share as there would be no effect on the amounts since the limited partners' share of income would also be added to derive net income attributable to common stockholders. We had unvested performance-based restricted stock awards of 453,664 shares and 619,429 shares for the three months ended June 30, 2018 and 2017, respectively, and 453,664 shares and 619,429 shares for the six months ended June 30, 2018 and 2017, respectively, which were excluded from the denominator of the diluted earnings per share as the awards had not achieved the requisite performance conditions for vesting at each period end.