Goodwill and Intangible Assets (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	$ 758,212	$ 739,814
Accumulated amortization	(60,710)	(48,121)
Total Intangible Assets Subject to Amortization, net	697,502	691,693
Intangible Assets with Indefinite Lives	0	0
Total Intangible Assets, net	697,502	691,693
Aggregate Amortization Expense for the Year	14,032	13,617
Contractual rights in place [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	640,450	628,707
Accumulated amortization	(35,748)	(29,100)
Noncompetition agreements [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	1,430	2,200
Accumulated amortization	(841)	(1,308)
Favorable lease agreements [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	16,677	16,677
Accumulated amortization	(2,031)	(1,531)
Permitting, permitting compliance and zoning rights [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	76,956	69,631
Accumulated amortization	(12,880)	(11,083)
Customer relationships [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	14,493	14,393
Accumulated amortization	(4,466)	(2,940)
Trade names and trademarks [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	5,006	5,006
Accumulated amortization	(1,544)	(1,043)
Other [Member]
Gross carrying amount and accumulated amortization by major intangible asset class
Gross carrying amount	3,200	3,200
Accumulated amortization	$ (3,200)	$ (1,116)