Consolidated Statements Of Cash Flows Unaudited - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash Flows from Operating Activities
Net income	$ 64,169	$ 65,400
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,656	14,225
Stock option expense	7,451	6,106
Benefit for deferred income taxes	(4,047)	(930)
Noncash long-term incentive compensation	1,185	1,642
Amortization of debt issuance costs	76	76
Payments on previously accrued litigation settlements		(8,490)
Changes in operating assets and liabilities:
Decrease in accounts receivable	19,610	22,773
(Increase)/decrease in inventories	(431)	318
Decrease in prepaid expenses	3,099	4,402
Decrease in accounts payable and other current liabilities	(30,332)	(18,369)
Change in current income taxes	23,530	18,395
Net change in lease assets and liabilities	743	(24)
Increase in other assets	(1,562)	(5,274)
Increase in other liabilities	2,958	5,759
Other (uses)/sources	(15)	710
Net cash provided by operating activities	101,090	106,719
Cash Flows from Investing Activities
Capital expenditures	(12,649)	(17,697)
Business combinations, net of cash acquired	(1,650)
Other sources	351	274
Net cash used by investing activities	(13,948)	(17,423)
Cash Flows from Financing Activities
Payments on revolving line of credit	(86,500)
Proceeds from revolving line of credit	21,500
Purchases of treasury stock	(27,794)	(41,107)
Proceeds from exercise of stock options	7,692	11,026
Change in cash overdraft payable	(7,051)
Dividends paid	(5,322)	(5,437)
Capital stock surrendered to pay taxes on stock-based compensation	(4,893)	(6,613)
Other sources	491	316
Net cash used by financing activities	(101,877)	(41,815)
(Decrease)/Increase in Cash and Cash Equivalents	(14,735)	47,481
Cash and cash equivalents at beginning of year	32,895	162,675
Cash and cash equivalents at end of period	$ 18,160	$ 210,156