Selected Quarterly Data (Tables)

12 Months Ended

Dec. 31, 2014

Quarterly Financial Information Disclosure [Abstract]

Summary of Selected Quarterly Data

	2014
($ in thousands, except share data)	Fourth Quarter		Third Quarter (1)		Second Quarter		First Quarter
Revenues	$	112,137	$	117,841	$	112,749	$	107,871
Operating Income		36,665		38,927		22,502		32,626
Net Income Attributable to Common Stockholders		18,879		37,340		19,543		21,938
Earnings per share—Basic	$	2.09	$	4.10	$	2.14	$	2.41
Earnings per share—Diluted	$	2.05	$	4.02	$	2.10	$	2.34

	2013
	Fourth Quarter		Third Quarter		Second Quarter		First Quarter
Revenues	$	106,498	$	100,409	$	96,140	$	86,168
Operating Income		33,892		31,630		26,882		21,100
Net Income Attributable to Common Stockholders		24,756		21,089		15,385		13,960
Earnings per share—Basic	$	2.72	$	2.64	$	1.97	$	1.79
Earnings per share—Diluted	$	2.65	$	2.56	$	1.91	$	1.73

(1) The third quarter of 2014 includes a net tax benefit of approximately $15.5 million due to completion of the audit of the Company’s 2011 federal corporate income tax return.