Quarterly financial data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly financial data (unaudited)

Schedule of unaudited quarterly results of operations

	Quarter Ended
	Mar 31,		Jun 30,		Sep 30,		Dec 31,		Mar 31,		Jun 30,		Sep 30,		Dec 31,
	2014		2014		2014		2014		2015		2015		2015		2015
	(in thousands, except per share data)
Revenues	$	246,285	$	256,325	$	261,939	$	285,944	$	278,315	$	304,702	$	313,126	$	326,697
Income before taxes		94,709		95,680		96,277		108,110		30,205		118,049		119,996		124,703
Net income		61,397		62,037		62,433		70,131		19,332		76,118		77,042		80,899
Net income per share:
Basic	$	0.60	$	0.61	$	0.61	$	0.68	$	0.19	$	0.74	$	0.75	$	0.79
Diluted	$	0.57	$	0.58	$	0.58	$	0.65	$	0.19	$	0.70	$	0.71	$	0.74