Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

Quarterly Financial Data (Unaudited)

Quarterly results of operations for the years ended December 31, 2015 and 2014 are summarized below:

	Three Months Ended
	March 31		June 30		September 30		December 31
	(in thousands, except per share amounts)
2015
Operating revenue	$	493,355	$	553,421	$	574,841	$	519,846
Operating income	109,251		122,315		157,219		120,337
Net income	69,002		76,704		97,114		74,400
Basic earnings per share	0.94		1.06		1.35		1.04
Diluted earnings per share	0.94		1.05		1.35		1.04
2014
Operating revenue	$	437,987	$	499,337	$	519,769	$	474,487
Operating income	59,953		105,144		100,191		89,975
Net income	37,706		64,849		67,000		55,909
Basic earnings per share	0.52		0.89		0.92		0.77
Diluted earnings per share	0.51		0.88		0.91		0.76