Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue	$ 528,060	$ 489,699	$ 1,029,818	$ 953,356
Cost of services	388,439	363,662	763,250	713,775
Gross profit	139,621	126,037	266,568	239,581
Selling, general and administrative expenses	56,491	53,137	112,366	103,349
Amortization of intangible assets	8,297	8,276	16,459	16,324
Income from operations	74,833	64,624	137,743	119,908
Interest expense — net	(11,723)	(12,161)	(23,671)	(23,664)
Income before income tax	63,110	52,463	114,072	96,244
Income tax expense	(13,783)	(12,037)	(22,703)	(18,520)
Net income	$ 49,327	$ 40,426	$ 91,369	$ 77,724
Earnings per common share:
Common stock — basic	$ 0.85	$ 0.70	$ 1.57	$ 1.33
Common stock — diluted	$ 0.83	$ 0.68	$ 1.55	$ 1.31
Weighted average number of common shares outstanding:
Common stock — diluted	58,939,763	58,761,229	58,846,073	59,104,631