Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows - operating activities:
Net income including noncontrolling interests	$ 173,995	$ 141,266
Depreciation and amortization	30,235	29,117
Amortization of identifiable intangible assets	36,320	30,678
Provision for doubtful accounts	6,027	3,962
Deferred income taxes	(5,991)	(830)
Excess tax benefits from share-based compensation	(1,565)	(2,062)
Equity income from unconsolidated entities	(1,132)	(719)
Other non-cash items	4,735	6,844
Distributions from unconsolidated entities	2,308	863
Changes in operating assets and liabilities, excluding the effect of businesses acquired	(6,648)	(80,195)
Net cash provided by operating activities	238,284	128,924
Cash flows - investing activities:
Payments for acquisitions of businesses, net of cash acquired	(82,724)	(232,883)
Proceeds from sale of property, plant and equipment	2,125	1,850
Purchase of property, plant and equipment	(26,113)	(29,306)
Net cash used in investing activities	(106,712)	(260,339)
Cash flows - financing activities:
Proceeds from revolving credit facility	0	220,000
Repayments of revolving credit facility	0	(95,000)
Borrowings from long-term debt	0	400,000
Repayments of long-term debt and debt issuance costs	(11,401)	(317,987)
Repayments of capital lease obligations	(1,079)	(1,144)
Dividends paid to stockholders	(14,266)	(14,598)
Repurchase of common stock	(90,944)	(34,805)
Proceeds from exercise of stock options	0	508
Payments to satisfy minimum tax withholding	(3,376)	(4,166)
Issuance of common stock under employee stock purchase plan	3,459	3,583
Payments for contingent consideration arrangements	(1,017)	0
Distributions to noncontrolling interests	0	(2,050)
Net cash (used in) provided by financing activities	(118,624)	154,341
Effect of exchange rate changes on cash and cash equivalents	2,931	(5,199)
Increase in cash and cash equivalents	15,879	17,727
Cash and cash equivalents at beginning of year	464,617	486,831
Cash and cash equivalents at end of period	480,496	504,558
Cash paid for:
Interest	8,507	7,920
Income taxes	95,584	98,176
Non-cash financing activities:
Assets acquired under capital lease obligations	$ 1,133	$ 1,738