Quarterly Results (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Results [Abstract]

Schedule of Quarterly Financial Information

	Year Ended December 31, 2018
	Fourth Quarter		Third Quarter		Second Quarter		First Quarter
Revenues	$	346,059	$	292,724	$	287,889	$	280,623
Gross profit		290,097		243,507		240,140		232,478
Net income		50,614		30,723		28,479		18,871
Net income per common share:
Basic	$	1.04	$	0.63	$	0.59	$	0.39
Diluted	$	1.03	$	0.61	$	0.57	$	0.38
Weighted average shares outstanding
Basic		47,967,014		48,009,953		47,951,326		47,873,007
Diluted		48,505,023		49,279,217		49,218,521		48,706,717
	Year Ended December 31, 2017
	Fourth Quarter		Third Quarter		Second Quarter		First Quarter
Revenues	$	316,380	$	273,616	$	273,174	$	254,669
Gross profit		270,406		231,245		230,015		213,859
Net income		49,871		32,358		31,376		25,820
Net income per common share:
Basic	$	1.03	$	0.67	$	0.65	$	0.54
Diluted	$	1.02	$	0.66	$	0.63	$	0.52
Weighted average shares outstanding
Basic		47,721,700		47,609,819		47,547,118		47,463,231
Diluted		48,437,580		48,521,082		48,948,315		48,766,031