Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows from Operating Activities
Net income	$ 55,891	$ 44,667
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,865	10,229
Stock option expense	5,045	4,089
Provision/(benefit) for deferred income taxes	2,290	(3,489)
Noncash long-term incentive compensation	1,598	1,119
Provision for bad debts	594
Amortization of debt issuance costs	76	76
Litigation settlement		6,000
Changes in operating assets and liabilities:
Decrease/(increase) in accounts receivable	6,269	(81)
Decrease/(increase) in inventories	149	(610)
Decrease in prepaid expenses	1,211	6
(Decrease)/increase in accounts payable and other current liabilities	(7,037)	348
Change in current income taxes	10,159	9,219
Net change in lease assets and liabilities	(153)	(328)
Decrease/(increase) in other assets	5,048	(5,006)
(Decrease)/increase in other liabilities	(6,067)	6,459
Other sources	388	887
Net cash provided by operating activities	89,326	73,585
Cash Flows from Investing Activities
Capital expenditures	(19,897)	(13,866)
Business combinations	(1,452)
Other uses	(144)	(68)
Net cash used by investing activities	(21,493)	(13,934)
Cash Flows from Financing Activities
Proceeds from revolving line of credit	174,100	125,100
Payments on revolving line of credit	(104,100)	(114,300)
Purchases of treasury stock	(100,235)	(49,250)
Change in cash overdrafts payable	(9,849)	(13,303)
Proceeds from exercise of stock options	9,241	11,827
Capital stock surrendered to pay taxes on stock-based compensation	(7,951)	(11,170)
Dividends paid	(5,130)	(4,799)
Other (uses)/sources	(1,116)	181
Net cash used by financing activities	(45,040)	(55,714)
Increase in Cash and Cash Equivalents	22,793	3,937
Cash and cash equivalents at beginning of year	6,158	4,831
Cash and cash equivalents at end of period	$ 28,951	$ 8,768