CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
CONSOLIDATED STATEMENTS OF OPERATIONS
REVENUE	$ 714,099	$ 706,918	$ 2,157,698	$ 1,895,693
COST OF SERVICES	566,903	564,216	1,747,714	1,526,310
Gross profit	147,196	142,702	409,984	369,383
SELLING, GENERAL AND ADMINISTRATIVE EXPENSES	90,888	90,006	268,857	253,417
GAIN ON SALE OF ASSETS	(377)	(708)	(1,243)	(1,119)
Operating income	56,685	53,404	142,370	117,085
OTHER INCOME (EXPENSE):
Interest income	7	82	99	174
Interest expense	(1,733)	(2,779)	(6,904)	(6,891)
Changes in the fair value of contingent earn-out obligations	3,423	(2,004)	1,824	(3,924)
Other	(15)	3	10	167
Other income (expense)	1,682	(4,698)	(4,971)	(10,474)
INCOME BEFORE INCOME TAXES	58,367	48,706	137,399	106,611
PROVISION FOR INCOME TAXES	8,279	12,473	30,100	26,339
NET INCOME	$ 50,088	$ 36,233	$ 107,299	$ 80,272
INCOME PER SHARE:
Basic (in shares)	$ 1.37	$ 0.98	$ 2.93	$ 2.18
Diluted (in shares)	$ 1.36	$ 0.98	$ 2.92	$ 2.16
SHARES USED IN COMPUTING INCOME PER SHARE:
Basic (in shares)	36,557	36,805	36,604	36,891
Diluted (in shares)	36,750	37,051	36,797	37,170
DIVIDENDS PER SHARE (in dollars per share)	$ 0.105	$ 0.100	$ 0.314	$ 0.295