Condensed, Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	[1]	$ 95,476	$ 81,823
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		40,163	39,797
Amortization of debt issue costs		870	604
Provision for uncollectible accounts		3,379	2,612
Net gain on sale or disposal of assets		(484)	(643)
Share-based compensation		8,269	8,571
Excess tax benefits from stock based compensation		(4,729)	(2,092)
Other		(658)	(53)
Changes in operating assets and liabilities:
Trade accounts receivable		(24,217)	(8,945)
Inventory, prepaid expenses and other assets		(8,942)	(6,610)
Accounts payable and other accrued liabilities		(4,196)	1,171
Accrued payroll and related liabilities		8,300	3,816
Income taxes		16,525	8,062
Net cash provided by operating activities		129,756	128,113
Cash flows from investing activities:
Business acquisitions, net of cash acquired		(66,529)	(30,764)
Property and equipment additions		(34,521)	(27,979)
Proceeds from sale or disposal of assets		6,164	4,456
Other		205	55
Net cash used in investing activities		(94,681)	(54,232)
Cash flows from financing activities:
Repayment of long-term obligations		(7,924)	(26,218)
Proceeds from revolving credit facility		61,000	0
Distributions to noncontrolling interest partners		(2,447)	(2,259)
Purchase of noncontrolling interests		(1,493)	(326)
Proceeds from issuance of common stock under stock incentive plans		679	467
Excess tax benefits from stock based compensation		4,729	2,092
Stock repurchases		(96,674)	(49,091)
Other		(80)	(838)
Net cash used in financing activities		(42,210)	(76,173)
Effect of currency exchange rate changes on cash and cash equivalents		78	(202)
Decrease in cash and cash equivalents		(7,057)	(2,494)
Cash and cash equivalents at beginning of period		81,383	125,029
Cash and cash equivalents at end of period		74,326	122,535
Supplemental disclosures of cash flow information:
Interest paid		8,907	7,491
Income taxes paid		44,253	42,950
Detail of acquisitions:
Fair value of assets acquired		75,973	34,329
Noncontrolling interest		0	(1,705)
Cash paid for acquisitions, net of acquired cash		(66,529)	(30,764)
Assumed debt		(6,250)	(736)
Contingent consideration		0	(374)
Holdbacks		(2,522)	(750)
Liabilities assumed		$ 672	$ 0

[1] Includes approximately $1.6 million and $1.2 million of net income related to redeemable and mandatorily redeemable noncontrolling interests for the six months ended June 30, 2015 and 2014, respectively.