Debt (Schedule Of Cash And Non-Cash Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instruments [Line Items]
Cash interest expense	$ 160,896	$ 149,921	$ 130,853
Non-cash interest expense	63,629	60,070	49,897
0.375% Convertible Senior Notes [Member]
Debt Instruments [Line Items]
Cash interest expense		46	195
Non-cash interest expense		1,755	3,695
Interest rates for senior notes	0.375%
1.875% Convertible Senior Notes [Member]
Debt Instruments [Line Items]
Cash interest expense	10,090	10,313	10,313
Non-cash interest expense	33,844	31,511	28,704
4.0% Convertible Senior Notes [Member]
Debt Instruments [Line Items]
Cash interest expense	20,000	20,000	13,767
Non-cash interest expense	29,149	25,643	15,838
8.0% Senior Notes [Member]
Debt Instruments [Line Items]
Cash interest expense	30,000	30,000	13,083
Non-cash interest expense	309	285	117
8.25% Senior Notes [Member]
Debt Instruments [Line Items]
Cash interest expense	30,938	30,938	13,492
Non-cash interest expense	237	218	90
2005 And 2006 CMBS Certificates [Member]
Debt Instruments [Line Items]
Cash interest expense		16,430	74,641
2010 Tower Securities [Member]
Debt Instruments [Line Items]
Cash interest expense	57,371	40,682
Term Loan [Member]
Debt Instruments [Line Items]
Cash interest expense	9,705
Non-cash interest expense	90
Revolving Credit Facility [Member]
Debt Instruments [Line Items]
Cash interest expense	3,209	1,903	3,756
Optasite Credit Facility [Member]
Debt Instruments [Line Items]
Cash interest expense			1,831
Non-cash interest expense			824
Gain/Loss On Swap [Member]
Debt Instruments [Line Items]
Non-cash interest expense		658	629
Capitalized Interest [Member]
Debt Instruments [Line Items]
Cash interest expense	$ (417)	$ (391)	$ (225)