Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2014

Earnings Per Share [Abstract]

Computation of Basic and Diluted Earnings per Share

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(in thousands, except per share data)	2014		2013		2014		2013
Net income attributable to common shareholders	$	28,079	$	57,131	$	136,460	$	169,796
Average basic shares outstanding	58,971		58,093		58,770		57,814
Effect of dilutive stock options	932		942		964		923
Average diluted shares outstanding	59,903		59,035		59,734		58,737
Earnings per basic share	$	0.48	$	0.98	$	2.32	$	2.94
Earnings per diluted share	$	0.47	$	0.97	$	2.28	$	2.89