CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
REVENUES
Customer services	$ 650,199	$ 583,698	$ 1,823,957	$ 1,624,928
COSTS AND EXPENSES
Cost of services provided	305,474	275,474	864,888	782,248
Depreciation and amortization	23,617	22,404	70,519	65,926
Sales, general and administrative	194,261	168,006	539,951	497,121
Chairman's accelerated stock vesting expense		6,691		6,691
(Gain) loss on sale of assets, net	(447)	1,355	(33,598)	629
Interest expense, net	222	866	1,334	4,491
INCOME BEFORE INCOME TAXES	127,072	108,902	380,863	267,822
PROVISION FOR INCOME TAXES	33,219	29,323	95,513	69,617
NET INCOME	$ 93,853	$ 79,579	$ 285,350	$ 198,205
NET INCOME PER SHARE - BASIC	$ 0.19	$ 0.16	$ 0.58	$ 0.40
NET INCOME PER SHARE - DILUTED	$ 0.19	$ 0.16	$ 0.58	$ 0.40
Weighted average shares outstanding - basic	492,069	491,631	492,058	491,236
Weighted average shares outstanding - diluted	492,069	492,058	491,631	491,236
DIVIDENDS PAID PER SHARE	$ 0.08	$ 0.05	$ 0.24	$ 0.19