CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONSOLIDATED STATEMENTS OF OPERATIONS
REVENUE	$ 706,918	$ 594,536	$ 1,895,693	$ 1,594,520
COST OF SERVICES	564,216	466,668	1,526,310	1,266,416
Gross profit	142,702	127,868	369,383	328,104
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	90,006	75,297	253,417	216,528
GAIN ON SALE OF ASSETS	(708)	(219)	(1,119)	(630)
Operating income	53,404	52,790	117,085	112,206
OTHER INCOME (EXPENSE):
Interest income	82	25	174	53
Interest expense	(2,779)	(1,152)	(6,891)	(2,601)
Changes in the fair value of contingent earn-out obligations	(2,004)	434	(3,924)	493
Other	3	39	167	4,062
Other income (expense)	(4,698)	(654)	(10,474)	2,007
INCOME BEFORE INCOME TAXES	48,706	52,136	106,611	114,213
PROVISION FOR INCOME TAXES	12,473	13,595	26,339	26,466
NET INCOME	$ 36,233	$ 38,541	$ 80,272	$ 87,747
INCOME PER SHARE:
Basic (in shares)	$ 0.98	$ 1.03	$ 2.18	$ 2.36
Diluted (in shares)	$ 0.98	$ 1.02	$ 2.16	$ 2.33
SHARES USED IN COMPUTING INCOME PER SHARE:
Basic (in shares)	36,805	37,294	36,891	37,236
Diluted (in shares)	37,051	37,667	37,170	37,634
DIVIDENDS PER SHARE (in dollars per share)	$ 0.100	$ 0.085	$ 0.295	$ 0.240