Condensed, Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	[1]	$ 114,148	$ 95,476
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		46,978	40,163
Amortization of debt issue costs		865	870
Provision for uncollectible accounts		2,891	3,379
Debt retirement costs		1,600	0
Net loss (gain) on sale or disposal of assets		292	(484)
Share-based compensation		9,104	8,269
Excess tax benefits from share-based compensation		(1,421)	(4,729)
Other		6,665	(658)
Changes in operating assets and liabilities:
Trade accounts receivable		(7,065)	(24,217)
Inventory, prepaid expenses and other assets		(15,607)	(8,942)
Accounts payable and other accrued liabilities		5,889	(4,196)
Accrued payroll and related liabilities		2,817	8,300
Income taxes		23,557	16,525
Net cash provided by operating activities		190,713	129,756
Cash flows from investing activities:
Business acquisitions, net of cash acquired		(540,878)	(66,529)
Property and equipment additions		(58,814)	(34,521)
Proceeds from sale or disposal of assets		282	6,164
Other		(4,924)	205
Net cash used in investing activities		(604,334)	(94,681)
Cash flows from financing activities:
Repayment of long-term obligations		(1,256,250)	(7,924)
Proceeds from issuance of long-term obligations		1,255,000	0
Proceeds from revolving credit facility		435,000	61,000
Payment of financing costs		(3,829)	0
Distribution to noncontrolling interests		(2,554)	(2,447)
Purchase of noncontrolling interests		(3,730)	(1,493)
Proceeds from issuance of common stock under stock incentive plans		1,122	679
Excess tax benefits from share-based compensation		1,421	4,729
Stock repurchases		(843)	(96,674)
Other		(1,233)	(80)
Net cash provided by (used in) financing activities		424,104	(42,210)
Effect of currency exchange rate changes on cash and cash equivalents		313	78
Increase (decrease) in cash and cash equivalents		10,796	(7,057)
Cash and cash equivalents at beginning of period		98,888	81,383
Cash and cash equivalents at end of period		109,684	74,326
Supplemental disclosures of cash flow information:
Interest paid		12,272	8,907
Income taxes paid		$ 47,326	$ 44,253

[1] Includes approximately $2.1 million and $1.6 million of net income related to redeemable and mandatorily redeemable noncontrolling interests for the six months ended June 30, 2016 and 2015, respectively.