Supplemental Cash Flow Information Significant Non-Cash Investing Activities(Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Significant Noncash Transactions [Line Items]
Accounts Receivable, Gross, Current	$ 265,642,000	$ 168,575,000
Purchases of property and equipment accrued in accounts payable	22,600,000	17,600,000	11,700,000
Accounts receivable - grants [Member]
Other Significant Noncash Transactions [Line Items]
Accounts Receivable, Gross, Current	$ 25,036,000	$ 20,753,000	$ 17,000,000