Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 140,683	[1]	$ 142,922	[1]	$ 50,716	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Impairment of goodwill and other long-lived assets	27,019		0		123,573
Depreciation and amortization	79,427		77,409		76,227
Amortization of debt issue costs	1,391		1,245		1,278
Provision for uncollectible accounts	6,248		7,360		6,396
Debt retirement costs	1,709		0		0
Business combination adjustment gain	0		0		(5,719)
Net (gain) loss on sale or disposal of assets	(1,152)		2,455		1,310
Share-based compensation	17,200		14,104		14,087
Deferred income taxes	8,853		18,064		(33,398)
Excess tax benefits from stock based compensation	(6,241)		(3,446)		(2,868)
Other	531		(377)		(584)
Changes in operating assets and liabilities:
Trade accounts receivable	(3,900)		(11,048)		1,640
Inventory, prepaid expenses and other assets	(22,897)		(7,134)		(10,329)
Accounts payable and other accrued liabilities	11,597		557		3,640
Accrued payroll and related liabilities	6,782		6,502		7,181
Income taxes	2,960		7,759		4,103
Net cash provided by operating activities	270,210		256,372		237,253
Cash flows from investing activities:
Real estate acquired in connection with business acquisitions	(9,017)		(5,328)		(5,337)
Property and equipment additions	(72,948)		(73,270)		(76,807)
Proceeds from sale or disposal of assets	3,904		7,096		115
Other	(2,691)		(2,541)		(2,313)
Net cash used in investing activities	(219,242)		(126,731)		(219,258)
Cash flows from financing activities:
Repayment of long-term obligations	(568,011)		(41,129)		(60,775)
Proceeds from the issuance of long-term obligations	600,000		0		50,000
Payment of financing costs	(7,987)		0		(122)
Proceeds from revolving credit facility	135,000		0		50,000
Repayment of revolving credit facility	0		0		(50,000)
Distributions to noncontrolling interest partners	(5,009)		(4,866)		(4,481)
Purchase of noncontrolling interests	(326)		(6,581)		0
Proceeds from issuance of common stock under stock incentive plans	2,859		17,233		9,533
Excess tax benefits from stock based compensation	6,241		3,446		2,868
Stock repurchases	(255,108)		(39,367)		(8,159)
Other	(1,424)		(749)		(2,378)
Net cash used in financing activities	(93,765)		(72,013)		(13,514)
Effect of currency exchange rate changes on cash and cash equivalents	(849)		(1,034)		303
(Decrease) increase in cash and cash equivalents	(43,646)		56,594		4,784
Cash and cash equivalents at beginning of year	125,029		68,435		63,651
Cash and cash equivalents at end of year	81,383		125,029		68,435
Supplemental disclosures of cash flow information:
Interest paid	15,049		16,422		15,407
Income taxes paid	75,098		61,825		61,481
Detail of acquisitions:
Fair value of assets acquired	157,956		75,445		220,526
Fair value of pre-existing investments	(2,014)		0		(11,850)
Noncontrolling interest	(933)		(3,336)
Cash paid for acquisitions, net of acquired cash	(138,490)		(52,688)		(134,916)
Assumed debt	(7,749)		(2,360)		(25,915)
Issuance of common stock for acquisitions	0		0		(10,500)
Contingent consideration	(2,797)		(1,285)		(1,306)
Holdbacks	(4,544)		(1,092)		(3,475)
Liabilities assumed	657		11,084		24,403
Capital lease additions	0		21,668		0
Series of Individually Immaterial Business Acquisitions
Detail of acquisitions:
Noncontrolling interest	$ (1,705)		$ (6,936)		$ (8,161)

[1] Includes $2.4 million, $3.3 million and $2.5 million for 2014, 2013 and 2012, respectively, related to redeemable and mandatorily redeemable noncontrolling interests.