Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows from Operating Activities:
Net Income	$ 235,658	$ 200,531	$ 188,353
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	151,227	153,651	122,945
Deferred income tax provision	7,502	31,184	21,631
Net gain on sales of property and equipment	(24,188)	(2,758)	(305)
Noncash compensation	12,529	8,490	6,369
Distributions from unconsolidated affiliates greater than earnings	2,262	5,569	5,194
Excluding the effects of acquisitions, increase (decrease) in cash from:
Accounts receivable	(99,537)	12,104	11,568
Inventory	(11,492)	(827)	3,365
Other operating assets	(62)	(30,074)	1,202
Currency translation effect on working capital	(10,589)	6,519	16,215
Accounts payable and accrued liabilites	8,968	56,100	8,036
Income taxes payable	14,484	(6,485)	25,578
Other operating liabilities	1,810	7,846	8,083
Total adjustments to net income	52,914	241,319	229,881
Net Cash Provided by Operating Activities	288,572	441,850	418,234
Cash Flows from Investing Activities:
Purchases of property and equipment	(235,028)	(185,262)	(175,021)
Business acquisitions, net of cash acquired	(291,617)	(21,918)	0
Dispositions of property and equipment and equity investment	43,874	15,284	12,535
Net Cash Used in Investing Activities	(482,771)	(191,896)	(162,486)
Cash Flows from Financing Activities:
Net Proceeds (payments) from revolving credit facility	120,000	(100,000)	(4,000)
Payments of 6.72% Senior Notes	0	(20,000)	(20,000)
Payments of Term Loan	0	0	(85,000)
Proceeds from issuance of common stock	0	693	1,880
Excess tax benefits from stock-based compensation	1,320	1,741	2,523
Cash dividends	(48,707)	0	0
Purchases of treasury stock	(17,491)	(49,520)	0
Net Cash Provided by (Used in) Financing Activities	55,122	(167,086)	(104,597)
Net Increase (Decrease) in Cash and Cash Equivalents	(139,077)	82,868	151,151
Cash and Cash Equivalents-Beginning of Period	245,219	162,351	11,200
Cash and Cash Equivalents-End of Period	$ 106,142	$ 245,219	$ 162,351