Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2014

Earnings Per Share [Abstract]

Earnings Per Share Summary

	Three Months Ended June 30,				Six Months Ended June 30,
($ thousands)	2014		2013		2014		2013
Numerator
Net income attributable to common stockholders	$	19,523	$	35,356	$	25,896	$	64,317
Less: adjustment for income allocated to participating securities		(2,683)		(127)		(3,543)		(243)
Net income attributable to common stockholders - basic and diluted	$	16,840	$	35,229	$	22,353	$	64,074
Denominator
Weighted average common shares outstanding - basic		86,887		87,865		87,559		87,823
Plus: dilutive effect of stock options and unvested restricted stock units		912		972		1,314		945
Weighted average common shares outstanding - diluted		87,799		88,837		88,873		88,768
Net income attributable per common share:
Basic	$	0.19	$	0.40	$	0.26	$	0.73
Diluted	$	0.19	$	0.40	$	0.25	$	0.72