CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues	$ 667,048	$ 629,401	$ 1,946,889	$ 1,819,529
Cost of services	448,733	422,281	1,317,493	1,222,541
Gross profit	218,315	207,120	629,396	596,988
Selling, general and administrative expenses	149,197	141,968	440,446	423,199
Amortization of intangible assets	8,248	9,742	25,011	29,918
Operating income	60,870	55,410	163,939	143,871
Interest expense	(7,099)	(8,294)	(21,667)	(25,278)
Income before income taxes	53,771	47,116	142,272	118,593
Provision for income taxes	18,892	17,341	51,775	45,457
Income from continuing operations	34,879	29,775	90,497	73,136
Income (loss) from discontinued operations, net of income taxes	(23)	(7)	(153)	37
Net income	$ 34,856	$ 29,768	$ 90,344	$ 73,173
Per share income from continuing operations and net income:
Basic	$ 0.66	$ 0.56	$ 1.72	$ 1.37
Diluted	$ 0.66	$ 0.55	$ 1.70	$ 1.36
Number of shares and share equivalents used to calculate earnings per share:
Basic	52,500	53,275	52,660	53,281
Diluted	53,173	53,768	53,319	53,787
Reconciliation of net income to comprehensive income:
Net income	$ 34,856	$ 29,768	$ 90,344	$ 73,173
Foreign currency translation adjustment	1,783	420	5,628	680
Comprehensive income	$ 36,639	$ 30,188	$ 95,972	$ 73,853