Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Data

	Quarter ended
(In thousands, except per share data)	March 31		June 30			September 30		December 31
2016
Total revenues	$	732,939	$	745,846		$	770,457	$	811,071
Insurance costs	569,689		596,673			609,422		637,968
Operating income	25,902		26,367			28,972		42,717
Net income	11,577		12,282			14,581		22,966
Basic net income per share	$	0.16	$	0.17		$	0.21	$	0.34
Diluted net income per share	$	0.16	$	0.17		$	0.20	$	0.32
2015
Total revenues	$	625,578	$	640,007		$	668,008	$	725,695
Insurance costs	483,203		517,994			534,481		576,698
Operating income	31,041		5,985			11,682		29,609
Net income (loss)	15,811		(1,308		)	3,097		14,095
Basic net income (loss) per share	$	0.23	$	(0.02	)	$	0.04	$	0.20
Diluted net income (loss) per share	$	0.22	$	(0.02	)	$	0.04	$	0.20