Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash Flows from Operating Activities
Net income	$ 121,922	$ 137,992
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30,347	28,012
Stock option expense	12,345	10,113
Litigation settlements paid	(9,440)
Noncash long-term incentive compensation	3,402	3,527
Noncash directors' compensation	1,173	1,171
Provision for deferred income taxes	1,051	2,717
Amortization of debt issuance costs	153	153
Provision for bad debts	40	871
Unutilized CARES Act grant		39,236
Deferred payroll taxes		10,716
Changes in operating assets and liabilities:
Decrease in accounts receivable	4,722	6,696
Increase in inventories	(316)	(5)
Decrease/(increase) in prepaid expenses	3,337	(33)
(Decrease)/increase in accounts payable and other current liabilities	(10,815)	13,303
Change in current income taxes	(26,242)	23,725
Net change in lease assets and liabilities	(436)	1,287
Increase in other assets	(10,088)	(2,988)
Increase in other liabilities	10,088	1,383
Other sources/(uses)	796	(54)
Net cash provided by operating activities	132,039	277,822
Cash Flows from Investing Activities
Capital expenditures	(33,604)	(32,251)
Business combinations		(3,600)
Other sources/(uses)	302	473
Net cash used by investing activities	(33,302)	(35,378)
Cash Flows from Financing Activities
Purchases of treasury stock	(166,649)	(122,148)
Proceeds from exercise of stock options	16,186	19,440
Dividends paid	(10,864)	(10,238)
Capital stock surrendered to pay taxes on stock-based compensation	(8,598)	(14,845)
Payments on revolving line of credit		(264,900)
Proceeds from revolving line of credit		174,900
Change in cash overdrafts payable		(9,849)
Other sources/(uses)	633	(586)
Net cash used by financing activities	(169,292)	(228,226)
(Decrease)/Increase in Cash and Cash Equivalents	(70,555)	14,218
Cash and cash equivalents at beginning of year	162,675	6,158
Cash and cash equivalents at end of period	$ 92,120	$ 20,376