Segment Information (Financial Information For Each Of The Company's Reporting Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Segment Reporting Information [Line Items]
Revenue from external customers	$ 197,738		$ 191,040
Cost of revenues	133,689		132,408
Selling, general, and administrative expenses	18,989		16,075
Acquisition-related expenses	2,822		1,087
Loss on disposal of assets	203		548
Adjusted EBITDA	48,526		44,484
Depreciation and accretion expense	16,285		13,750
Amortization expense	5,748		5,475
Interest expense, net, including amortization of deferred financing costs	5,295		5,585
Income tax expense	5,980		6,146
Capital expenditures	15,937	[1]	21,686	[1]
U.S. [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	157,156		157,955
Intersegment revenues	1,837		1,276
Cost of revenues	102,865		107,502
Selling, general, and administrative expenses	15,983		13,926
Acquisition-related expenses	2,800		878
Loss on disposal of assets	183		539
Adjusted EBITDA	43,293		40,347
Depreciation and accretion expense	10,078		8,507
Amortization expense	5,218		4,891
Interest expense, net, including amortization of deferred financing costs	5,040		5,333
Income tax expense	5,980		6,146
Capital expenditures	11,911	[1]	16,129	[1]
U.K. [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	29,499		25,191
Cost of revenues	23,420		20,208
Selling, general, and administrative expenses	2,126		1,539
Acquisition-related expenses			209
Loss on disposal of assets	7		2
Adjusted EBITDA	4,399		3,443
Depreciation and accretion expense	5,076		4,465
Amortization expense	354		548
Interest expense, net, including amortization of deferred financing costs	173		138
Capital expenditures	3,894	[1]	5,068	[1]
Other International [Member]
Segment Reporting Information [Line Items]
Revenue from external customers	11,083		7,894
Intersegment revenues	17		36
Cost of revenues	9,238		6,009
Selling, general, and administrative expenses	880		610
Acquisition-related expenses	22
Loss on disposal of assets	13		7
Adjusted EBITDA	854		695
Depreciation and accretion expense	1,167		783
Amortization expense	176		36
Interest expense, net, including amortization of deferred financing costs	82		114
Capital expenditures	133	[1]	489	[1]
Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment revenues	(1,854)		(1,312)
Cost of revenues	(1,834)		(1,311)
Adjusted EBITDA	(20)		(1)
Depreciation and accretion expense	(36)		(5)
Capital expenditures	$ (1)	[1]

[1] Capital expenditure amounts include payments made for exclusive license agreements and site acquisition. Additionally, capital expenditure amounts for Mexico (included in the Other International segment) are reflected gross of any noncontrolling interest amounts.