Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]



	Quarter
	First		Second		Third		Fourth			Full Year
	(In thousands, except per share data)
Year Ended December 31,
2016
Total revenues	$	2,608,355	$	2,782,449	$	2,823,176	$	2,673,632		$	10,887,612
Gross profit	389,101		410,119		406,668		389,181			1,595,069
Net income	34,291		46,580		35,366		30,828			147,065
Basic earnings per share ⁽¹⁾	1.47		2.12		1.65		1.44			6.67
Diluted earnings per share ⁽¹⁾	1.47		2.12		1.65		1.44			6.67
2015
Total revenues	$	2,432,854	$	2,726,480	$	2,800,569	$	2,672,602		$	10,632,505
Gross profit	363,884		391,573		398,382		380,133			1,533,972
Net income	35,815		46,310		45,261		(33,387		)	93,999
Basic earnings per share ⁽¹⁾	1.47		1.91		1.88		(1.41		)	3.91
Diluted earnings per share ⁽¹⁾	1.47		1.91		1.88		(1.41		)	3.90

⁽¹⁾ The sum of the quarterly income per share amounts may not equal the annual amount reported, as per share amounts are computed independently for each quarter and for the full year based on the respective weighted average common shares outstanding.