Supplemental Guarantor Financial Information (Condensed Consolidating Statements Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net cash (used in) provided by operating activities	$ 183,557	$ 136,388	$ 113,325
Additions to property and equipment	(71,562)	(89,579)	(64,418)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(5,591)	(3,224)	(2,468)
Acquisitions, net of cash acquired	(189,587)	(20,961)	(167,568)
Net cash used in investing activities	(266,740)	(113,764)	(234,454)
Proceeds from borrowing of long-term debt	311,277	245,100	381,738
Repayments of long-term debt and capital leases	(397,667)	(261,596)	(264,991)
Proceeds from issuance of convertible notes	287,500
Proceeds from issuance of warrants	40,509
Purchase of convertible note hedges	(72,565)
Debt issuance and modification costs	(7,540)		(655)
Payment of contingent acquisition consideration	(750)
Repayments of borrowings under bank overdraft facility, net		(162)	(830)
Proceeds from exercises of stock options	2,626	7,344	11,420
Excess tax benefit from stock-based compensation expense	24,007
Repurchase of capital stock	(32,409)	(4,770)	(3,150)
Net cash provided by financing activities	154,988	(14,084)	123,532
Effect of exchange rate changes on cash	1,273	(255)	(16)
Net increase (decrease) in cash and cash equivalents	73,078	8,285	2,387
Cash and cash equivalents as of beginning of period	13,861	5,576	3,189
Cash and cash equivalents as of end of period	86,939	13,861	5,576
Elimination [Member]
Net cash (used in) provided by operating activities	(49)	(383)
Intercompany fixed asset mark-up	49	383
Investment in subsidiary	212,348		100,048
Funding of intercompany notes payable	338,366	221,672	316,231
Payments received on intercompany notes payable	(333,569)	(223,680)	(282,703)
Net cash used in investing activities	217,194	(1,625)	133,576
Proceeds from intercompany notes payable	(338,366)	(221,672)	(316,231)
Repayments of intercompany notes payable	333,569	223,680	282,703
Issuance of capital stock	(212,348)		(100,048)
Net cash provided by financing activities	(217,145)	2,008	(133,576)
Parent [Member]
Net cash (used in) provided by operating activities	(39,202)	(2,375)	2,496
Investment in subsidiary	(80,680)
Funding of intercompany notes payable	(335,266)	(209,875)	(316,231)
Payments received on intercompany notes payable	298,303	223,680	189,040
Acquisitions, net of cash acquired			(2,800)
Net cash used in investing activities	(117,643)	13,805	(129,991)
Proceeds from borrowing of long-term debt	311,277	245,100	381,738
Repayments of long-term debt and capital leases	(396,153)	(259,100)	(261,938)
Proceeds from issuance of convertible notes	287,500
Proceeds from issuance of warrants	40,509
Purchase of convertible note hedges	(72,565)
Debt issuance and modification costs	(7,540)		(655)
Proceeds from exercises of stock options	2,626	7,344	11,420
Excess tax benefit from stock-based compensation expense	24,007
Repurchase of capital stock	(32,409)	(4,770)	(3,150)
Net cash provided by financing activities	157,252	(11,426)	127,415
Net increase (decrease) in cash and cash equivalents	407	4	(80)
Cash and cash equivalents as of beginning of period	5	1	81
Cash and cash equivalents as of end of period	412	5	1
Guarantors [Member]
Net cash (used in) provided by operating activities	193,206	116,424	100,460
Additions to property and equipment	(50,414)	(60,932)	(45,640)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(2,609)	(1,564)	(514)
Investment in subsidiary	(131,668)		(100,048)
Funding of intercompany notes payable	(3,100)	(11,797)
Payments received on intercompany notes payable	35,266		93,663
Acquisitions, net of cash acquired	(19,997)	(17,661)	(164,811)
Net cash used in investing activities	(172,522)	(91,954)	(217,350)
Repayments of long-term debt and capital leases	(11)	(11)	(3)
Proceeds from intercompany notes payable	168,604	205,174	308,294
Repayments of intercompany notes payable	(206,775)	(223,680)	(188,899)
Payment of contingent acquisition consideration	(750)
Issuance of capital stock	80,953
Net cash provided by financing activities	42,021	(18,517)	119,392
Net increase (decrease) in cash and cash equivalents	62,705	5,953	2,502
Cash and cash equivalents as of beginning of period	10,674	4,721	2,219
Cash and cash equivalents as of end of period	73,379	10,674	4,721
Non-Guarantors [Member]
Net cash (used in) provided by operating activities	29,602	22,722	10,369
Additions to property and equipment	(21,148)	(28,647)	(18,778)
Payments for exclusive license agreements, site acquisition costs and other intangible assets	(2,982)	(1,660)	(1,954)
Intercompany fixed asset mark-up	(49)	(383)
Acquisitions, net of cash acquired	(169,590)	(3,300)	43
Net cash used in investing activities	(193,769)	(33,990)	(20,689)
Repayments of long-term debt and capital leases	(1,503)	(2,485)	(3,050)
Proceeds from intercompany notes payable	169,762	16,498	7,937
Repayments of intercompany notes payable	(126,794)		(93,804)
Repayments of borrowings under bank overdraft facility, net		(162)	(830)
Issuance of capital stock	131,395		100,048
Net cash provided by financing activities	172,860	13,851	10,301
Effect of exchange rate changes on cash	1,273	(255)	(16)
Net increase (decrease) in cash and cash equivalents	9,966	2,328	(35)
Cash and cash equivalents as of beginning of period	3,182	854	889
Cash and cash equivalents as of end of period	$ 13,148	$ 3,182	$ 854