Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Reconciliation between Basic and Diluted Weighted Average Shares Outstanding

	For the three months   ended June 30,						For the six months   ended June 30,
(in thousands, except per share data)	2018			2017			2018			2017
Net income	$	73,922		$	66,102		$	164,750		$	136,212
Net income attributable to unvested awarded performance stock	(1,618		)	(1,642		)	(3,529		)	(3,329		)
Net income attributable to common shares	$	72,304		$	64,460		$	161,221		$	132,883
Weighted average number of common shares outstanding – basic	276,123			280,346			276,038			280,286
Less unvested awarded performance stock included in weighted average number of common shares outstanding – basic	(6,042		)	(6,962		)	(5,912		)	(6,850		)
Weighted average number of common shares outstanding for basic net income per common share	270,081			273,384			270,126			273,436
Dilutive effect of stock options	5,827			4,818			5,683			4,692
Weighted average number of shares outstanding – diluted	275,908			278,202			275,809			278,128
Net income per share:
Basic	$	0.27		$	0.24		$	0.60		$	0.49
Diluted	$	0.26		$	0.23		$	0.58		$	0.48