Segment Information (Financial Information For Each Of The Company's Reporting Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenue from external customers	$ 174,182	$ 165,059	$ 147,294	$ 138,041	$ 134,749	$ 136,605	$ 132,948	$ 127,776	$ 624,576		$ 532,078		$ 493,353
Cost of revenues									420,115		360,392		344,474
Selling, general, and administrative expenses									55,582		44,581		41,527
Acquisition-related expenses									4,747
Loss on disposal of assets									981		2,647		6,016
Adjusted EBITDA									156,307		130,819		110,373
Depreciation and accretion expense									47,962		42,724		39,420
Amortization expense									17,914		15,471		18,916
Interest expense, net									21,109		28,658		32,528
Write-off of deferred financing costs and bond discounts											7,296
Redemption costs for early extinguishment of debt											7,193
Income tax (benefit) expense									(13,176)		(17,139)		4,245
Capital expenditures									66,886	[1]	51,194	[1]	28,530	[1]
U.S. [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									501,439		423,109		401,934
Intersegment revenues									4,277		3,071		2,142
Cost of revenues									329,782		280,973		281,724
Selling, general, and administrative expenses									47,342		37,598		35,434
Acquisition-related expenses									4,747
Loss on disposal of assets									791		1,135		2,809
Adjusted EBITDA									137,840		113,567		93,105
Depreciation and accretion expense									28,719		27,342		26,845
Amortization expense									15,985		13,517		17,127
Interest expense, net									17,144		23,598		26,893
Write-off of deferred financing costs and bond discounts											7,296
Redemption costs for early extinguishment of debt											7,193
Income tax (benefit) expense									(13,176)		(17,139)		4,245
Capital expenditures									46,154	[1]	34,749	[1]	16,245	[1]
U.K. [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									97,665		82,583		73,096
Cost of revenues									75,109		62,386		51,419
Selling, general, and administrative expenses									5,950		5,106		4,865
Loss on disposal of assets									215		1,305		3,106
Adjusted EBITDA									16,554		14,966		15,418
Depreciation and accretion expense									16,194		12,541		10,799
Amortization expense									1,892		1,931		1,749
Interest expense, net									3,260		4,105		4,976
Capital expenditures									20,478	[1]	13,059	[1]	6,714	[1]
Other International [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									25,472		26,386		18,323
Intersegment revenues									111
Cost of revenues									19,612		20,104		13,473
Selling, general, and administrative expenses									2,290		1,877		1,228
Loss on disposal of assets									(25)		207		101
Adjusted EBITDA									1,913		2,286		1,850
Depreciation and accretion expense									3,070		2,862		1,797
Amortization expense									37		23		40
Interest expense, net									705		955		659
Capital expenditures									254	[1]	3,386	[1]	5,571	[1]
Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment revenues									(4,388)		(3,071)		(2,142)
Cost of revenues									(4,388)		(3,071)		(2,142)
Depreciation and accretion expense									$ (21)		$ (21)		$ (21)

[1] Capital expenditure amounts include payments made for exclusive license agreements, site acquisition costs, and capital expenditures financed by direct debt. Additionally, capital expenditure amounts for Mexico are reflected gross of any noncontrolling interest amounts.