Debt (Schedule Of Cash And Non-Cash Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May 16, 2008	Oct. 15, 2014	Apr. 24, 2009	Jul. 24, 2009	Sep. 28, 2012	Jul. 13, 2012	Jul. 01, 2014
Debt Instrument [Line Items]
Cash Interest	$ 292,600	$ 249,051	$ 196,241
Non-cash Interest	27,112	49,085	70,110
1.875% Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest		2,670	9,885
Non-cash Interest		10,434	36,388
Debt instrument, interest rate, stated percentage	1.875%			1.875%
4.0% Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest	12,520	19,998	20,000
Non-cash Interest	26,266	38,307	33,149
Debt instrument, interest rate, stated percentage	4.00%				4.00%	4.00%
8.0% Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest			15,867
Non-cash Interest			174
Debt instrument, interest rate, stated percentage	8.00%						8.00%
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest	12,513	20,109	23,177
Non-cash Interest	121	182	192
Debt instrument, interest rate, stated percentage	8.25%						8.25%
5.625% Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest	28,125	28,125	7,266
Debt instrument, interest rate, stated percentage	5.625%							5.625%
5.75% Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest	46,000	46,000	21,594
Debt instrument, interest rate, stated percentage	5.75%	5.75%							5.75%
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Cash Interest	18,281
Non-cash Interest	315
Debt instrument, interest rate, stated percentage	4.875%		4.875%							4.875%
2010 Tower Securities [Member]
Debt Instrument [Line Items]
Cash Interest	51,237	57,383	57,377
2012 Tower Securities [Member]
Debt Instrument [Line Items]
Cash Interest	18,085	18,085	7,133
2013 Tower Securities [Member]
Debt Instrument [Line Items]
Cash Interest	43,217	30,392
2014 Tower Securities [Member]
Debt Instrument [Line Items]
Cash Interest	10,796
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Cash Interest	4,591	4,515	4,392
2011 Term Loan [Member]
Debt Instrument [Line Items]
Cash Interest	696	10,533	18,894
Non-cash Interest	7	101	179
2012-1 Term Loan [Member]
Debt Instrument [Line Items]
Cash Interest	4,534	4,557	3,567
2012-2 Term Loan [Member]
Debt Instrument [Line Items]
Cash Interest	424	6,416	2,969
Non-cash Interest	4	61	28
2014 Term Loan [Member]
Debt Instrument [Line Items]
Cash Interest	41,338
Non-cash Interest	399
Mobilitie Bridge Loan [Member]
Debt Instrument [Line Items]
Cash Interest			4,239
Other [Member]
Debt Instrument [Line Items]
Cash Interest	$ 243	$ 268	$ (119)