Net Income Per Share (Tables)

6 Months Ended

Jun. 30, 2017

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)	2017			2016			2017			2016
Net income	$	66,102		$	66,250		$	136,212		$	128,320
Net income attributable to unvested awarded performance stock	(1,642		)	(1,896		)	(3,329		)	(3,337		)
Net income attributable to common shares	$	64,460		$	64,354		$	132,883		$	124,983
Weighted average number of common shares outstanding – basic	140,173			139,998			140,143			139,395
Less unvested awarded performance stock included in weighted average number of common shares outstanding – basic	(3,481		)	(4,006		)	(3,425		)	(3,625		)
Weighted average number of common shares outstanding for basic earnings per common share	136,692			135,992			136,718			135,770
Dilutive effect of stock options	2,409			1,589			2,346			1,490
Weighted average number of shares outstanding – diluted	139,101			137,581			139,064			137,260
Net income per share:
Basic	$	0.47		$	0.47		$	0.97		$	0.92
Diluted	$	0.46		$	0.47		$	0.96		$	0.91