Supplemental Guarantor Financial Information (Condensed Consolidating Statements Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net cash provided by operating	$ 113,325	$ 105,168	$ 74,874
Additions to property and equipment	(64,418)	(48,069)	(25,770)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(2,468)	(2,583)	(261)
Acquisitions, net of cash acquired	(167,568)
Net cash provided by (used in) investing activities	(234,454)	(50,652)	(26,031)
Proceeds from borrowings of long-term debt	381,738	382,400	55,882
Repayments of long-term debt and capital leases	(264,991)	(445,840)	(99,212)
Repayments of borrowings under bank overdraft facility, net	(830)	995	(142)
Debt issuance and modification costs	(655)	(5,423)	(458)
Proceeds from exercises of stock options	11,420	7,390	1,596
Repurchase of capital stock	(3,150)	(1,672)	(458)
Payments received on subscriptions receivable			34
Noncontrolling interest stockholder capital contributions			526
Net cash provided by (used in) financing activities	123,532	(62,150)	(42,232)
Effect of exchange rate changes on cash	(16)	374	414
Net increase (decrease) in cash and cash equivalents	2,387	(7,260)	7,025
Cash and cash equivalents as of beginning of period	3,189	10,449	3,424
Cash and cash equivalents as of end of period	5,576	3,189	10,449
Parent [Member]
Net cash provided by operating	2,496	5,459	(23,776)
Investments in subsidiary			(548)
Issuance of long-term notes receivable	(316,231)	(29,220)	(30,500)
Payments received on long-term notes receivable	189,040	84,500	97,630
Acquisitions, net of cash acquired	(2,800)
Net cash provided by (used in) investing activities	(129,991)	55,280	66,582
Proceeds from borrowings of long-term debt	381,738	382,400	53,500
Repayments of long-term debt and capital leases	(261,938)	(443,393)	(97,000)
Debt issuance and modification costs	(655)	(5,423)	(458)
Proceeds from exercises of stock options	11,420	7,390	1,596
Repurchase of capital stock	(3,150)	(1,672)	(458)
Payments received on subscriptions receivable			34
Net cash provided by (used in) financing activities	127,415	(60,698)	(42,786)
Net increase (decrease) in cash and cash equivalents	(80)	41	20
Cash and cash equivalents as of beginning of period	81	40	20
Cash and cash equivalents as of end of period	1	81	40
Guarantors [Member]
Net cash provided by operating	100,460	84,083	90,365
Additions to property and equipment	(45,640)	(32,373)	(16,189)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(514)	(2,376)	(55)
Investments in subsidiary	(100,048)
Payments received on long-term notes receivable	93,663
Acquisitions, net of cash acquired	(164,811)
Net cash provided by (used in) investing activities	(217,350)	(34,749)	(16,244)
Proceeds from borrowings of long-term debt	308,294	29,220	29,501
Repayments of long-term debt and capital leases	(188,902)	(84,735)	(98,387)
Net cash provided by (used in) financing activities	119,392	(55,515)	(68,886)
Net increase (decrease) in cash and cash equivalents	2,502	(6,181)	5,235
Cash and cash equivalents as of beginning of period	2,219	8,400	3,165
Cash and cash equivalents as of end of period	4,721	2,219	8,400
Non-Guarantors [Member]
Net cash provided by operating	10,369	15,626	8,285
Additions to property and equipment	(18,778)	(15,696)	(9,581)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(1,954)	(207)	(206)
Acquisitions, net of cash acquired	43
Net cash provided by (used in) investing activities	(20,689)	(15,903)	(9,787)
Proceeds from borrowings of long-term debt	7,937		3,381
Repayments of long-term debt and capital leases	(96,854)	(2,212)	(1,455)
Repayments of borrowings under bank overdraft facility, net	(830)	995	(142)
Issuance of capital stock	100,048		548
Noncontrolling interest stockholder capital contributions			526
Net cash provided by (used in) financing activities	10,301	(1,217)	2,858
Effect of exchange rate changes on cash	(16)	374	414
Net increase (decrease) in cash and cash equivalents	(35)	(1,120)	1,770
Cash and cash equivalents as of beginning of period	889	2,009	239
Cash and cash equivalents as of end of period	854	889	2,009
Elimination [Member]
Investments in subsidiary	100,048		548
Issuance of long-term notes receivable	316,231	29,220	30,500
Payments received on long-term notes receivable	(282,703)	(84,500)	(97,630)
Net cash provided by (used in) investing activities	133,576	(55,280)	(66,582)
Proceeds from borrowings of long-term debt	(316,231)	(29,220)	(30,500)
Repayments of long-term debt and capital leases	282,703	84,500	97,630
Issuance of capital stock	(100,048)		(548)
Net cash provided by (used in) financing activities	$ (133,576)	$ 55,280	$ 66,582