Goodwill, Intangible Assets and In-Process Revenue Contracts (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Acquired finite lived intangible assets by major class
Weighted-Average Amortization Period	15 years 2 months	13 years 5 months
Gross carrying amount	$ 341,245	$ 358,515
Accumulated Amortization	(204,503)	(202,622)
Net Carrying Amount	136,742	155,893
Customer Contracts [Member]
Acquired finite lived intangible assets by major class
Weighted-Average Amortization Period	15 years 6 months	13 years 7 months
Gross carrying amount	329,815	347,085
Accumulated Amortization	(194,266)	(195,358)
Net Carrying Amount	135,549	151,727
Other Intangible Assets [Member]
Acquired finite lived intangible assets by major class
Weighted-Average Amortization Period	4 years 5 months	4 years 5 months
Gross carrying amount	11,430	11,430
Accumulated Amortization	(10,237)	(7,264)
Net Carrying Amount	$ 1,193	$ 4,166

Sum of the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible assets having statutory or estimated useful lives. The aggregate gross carrying amount (including any previously recognized impairment charges) of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant