Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Cash Flows from Operating Activities:
Net income	$ 187,794		$ 178,287		$ 161,754
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	54,596		52,408		48,202
Loss on disposal of property and equipment	170		226		615
Increase (decrease) in deferred compensation liability	444		184		(171)
Gain on disposition of pharmaceutical product lines			(3,500)		(3,000)
Provision for uncollectible accounts	1,601		1,108		1,484
Provision for (benefit of) deferred income taxes	2,073		(1,970)		5,996
Share-based compensation expense	16,539		15,952		15,496
Tax benefit from share-based compensation arrangements	(14,158)		(14,676)		(16,007)
Changes in assets and liabilities:
Accounts receivable	(15,946)		3,487		(24,809)
Inventories	(1,347)		(17,208)		(7,579)
Other assets	(4,325)		3,933		(1,339)
Accounts payable	(4,399)		(2,898)		13,015
Accrued liabilities	16,512		187		16,915
Deferred revenue	6,442		6,888		7,341
Net cash provided by operating activities	245,996		222,408		217,913
Cash Flows from Investing Activities:
Purchases of property and equipment	(77,612)	[1]	(57,618)	[1]	(49,677)	[1]
Proceeds from disposition of pharmaceutical product lines	3,500		3,000		3,000
Proceeds from sale of property and equipment			45		225
Acquisitions of intangible assets	(1,024)		(900)		(1,000)
Acquisition of businesses, net of cash acquired	(10,923)		(2,658)		(46,757)
Net cash used by investing activities	(86,059)		(58,131)		(94,209)
Cash Flows from Financing Activities:
Borrowings (payments) on revolving credit facilities, net	65,000		(31,000)		113,903
Issuance of senior notes	150,000
Debt issue costs	(976)
Payment of notes payable	(1,107)		(917)		(863)
Repurchases of common stock	(367,761)		(132,268)		(255,505)
Proceeds from exercises of stock options and employee stock purchase plans	38,235		24,166		28,801
Tax benefit from share-based compensation arrangements	14,158		14,676		16,007
Net cash used by financing activities	(102,451)		(125,343)		(97,657)
Net effect of changes in exchange rates on cash	(2,414)		1,157		933
Net increase in cash and cash equivalents	55,072		40,091		26,980
Cash and cash equivalents at beginning of period	223,986		183,895		156,915
Cash and cash equivalents at end of period	279,058		223,986		183,895
Supplemental Disclosures of Cash Flow Information
Interest paid	5,024		3,944		3,763
Income taxes paid	67,721		68,921		44,347
Supplemental Disclosure of Non-Cash Information:
Market value of common shares received from employees in connection with share-based compensation - see Note 18	4,548		4,662		4,316
Receivable on disposition of pharmaceutical product lines			$ 3,500		$ 3,000

[1] __________(1) Expenditures for long-lived assets exclude expenditures for intangible assets. See Note 3 for information regarding acquisitions of intangible assets during the years ended December 31, 2013, 2012 and 2011.