Notes Payable, Long Term Debt and Other Obligations - Textuals (Details)							1 Months Ended			12 Months Ended
	Feb. 03, 2015 USD ($) shares	Apr. 15, 2014 USD ($)	Mar. 24, 2014 USD ($) $ / shares shares	Mar. 14, 2014 USD ($) shares	Jan. 29, 2013 USD ($)	May. 11, 2009 USD ($)	Feb. 28, 2013 USD ($)	Nov. 30, 2012 USD ($) $ / shares shares	Jul. 31, 2006 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Nov. 30, 2013 USD ($) shares	Mar. 14, 2013 USD ($)	Jan. 31, 2013 USD ($)	Nov. 04, 2011	Nov. 30, 2009
Debt Instrument [Line Items]
Fair value of derivatives embedded within convertible debt										$ 144,042,000	$ 168,502,000
Subsidiary Guarantors, Percentage Ownership										100.00%
Proceeds from issuance of debt										$ 2,105,000	413,914,000	$ 457,767,000
Loss on extinguishment of debt										0	0	21,458,000
Acceleration of interest expense related to debt conversion										0	5,205,000	12,414,000
Acceleration of interest expense related to debt conversion										0	5,205,000	12,414,000
Long-term Debt, Gross										1,105,409,000
Long-term Debt										895,168,000	913,351,000
Non-cash interest expense (income)										(6,504,000)	(35,584,000)	(22,995,000)
Interest expense associated with embedded derivatives										18,529,000	32,071,000	21,482,000
6.75% Variable Interest Senior Convertible Note Due 2014 [Member]
Debt Instrument [Line Items]
Fair value of derivatives embedded within convertible debt										0	884,000
5.5% Variable Interest Senior Convertible Debentures due 2020 [Member]
Debt Instrument [Line Items]
Fair value of derivatives embedded within convertible debt										71,959,000	80,864,000
7.5% Variable Interest Senior Convertible Notes due 2019 [Member]
Debt Instrument [Line Items]
Fair value of derivatives embedded within convertible debt										72,083,000	87,638,000
Executive Vice President [Member]
Debt Instrument [Line Items]
Stock Ownership In Company Percentage																		15.30%
Jefferies & Company Inc. [Member]
Debt Instrument [Line Items]
Own-share Lending Arrangement, Shares, Issued | shares								7,077,720
Own-share Lending Arrangement, Nominal Lending Fee Per Share | $ / shares								$ 0.10
Own-share Lending Arrangement, Shares, Outstanding, Value								$ 3,204,000
Own-share Lending Arrangement, Shares Returned | shares								3,538,860
Own-share Lending Arrangement, Shares, Outstanding | shares								3,538,859
Own-share Lending Arrangement, Amount Amortized								$ 286,000
Secured Debt [Member] | 11% Senior Secured Notes Due 2015 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage					11.00%
Interest Rate																	7.75%
Face amount					$ 415,000,000											$ 78,685,000	$ 600,000,000
Repayments of Long-term Debt					$ 336,315,000
Debt Instrument, Redemption Price, Percentage				103.667%	104.292%
Loss on extinguishment of debt										21,458,000
Redemption Premium										17,820,000
Non-cash interest expense (income)										3,638,000
Secured Debt [Member] | 7.75% Senior Secured Notes Due 2021 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage							7.75%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed		106.75%
Face amount		$ 150,000,000					$ 450,000,000
Subsidiary Guarantors, Percentage Ownership							100.00%
Proceeds from issuance of debt		$ 158,670,000					$ 438,250,000
Debt Redemption Price as a Percentage of Principal Amount							107.75%
Mandatory Redemption Percent In Event Of Change In Control							101.00%
Maximum Term to Consummate Registered Exchange Offer							360 days
Indenture Threshold for Earnings for Payment of Dividends							$ 75,000,000
Debt Instrument, Percent of Principal							35.00%
Long-term Debt										$ 608,014,000	609,275,000
Leverage Ratio Requirement							3.0
Secured Leverage Ratio Requirement							1.5
Convertible Debt [Member]
Debt Instrument [Line Items]
Term Before Record Date to Determine Additional Interest										3 years
Convertible Debt [Member] | 5% Variable Interest Senior Convertible Notes due November 15, 2011 [Member]
Debt Instrument [Line Items]
Interest Rate										5.00%
Principal Amount Of Debt Sold						$ 11,005,000
Debt instrument, premium percentage																			107.00%
Convertible Debt [Member] | 6.75% Variable Interest Senior Convertible Note Due 2014 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage				6.75%						6.75%
Proceeds from private placement debt offering						$ 38,225,000
Debt Conversion, Original Debt, Interest Rate of Debt						3.75%
Period for Prior Cash Dividend Paid										3 months
Note conversion, net of income taxes (in shares) | shares	2,338,930			2,338,930
Debt Conversion, Original Debt, Amount	$ 50,000,000
Debt Conversion, Converted Instrument, Amount				$ 25,000,000
Acceleration of interest expense related to debt conversion										$ 3,679,000
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt										25,000,000
Long-term Debt				$ 0						$ 0	25,000,000
Convertible Debt [Member] | 3.875% Senior Convertible Debentures [Member]
Debt Instrument [Line Items]
Interest rate effective percentage										3.875%
Face amount															$ 43,222,000
Convertible Preferred Stock, Shares Issued upon Conversion | shares															3,274,610
Principal Amount Of Debt Sold									$ 110,000,000
Debt Conversion, Original Debt, Amount													$ 55,778,000	$ 11,000,000
Acceleration of interest expense related to debt conversion										$ 12,414,000
Debt Reclassified from Debt to Equity										43,222,000
Interest expense associated with embedded derivatives										$ 0	0	$ 155,000
Convertible Debt [Member] | 6.75% Variable Interest Senior Convertible Exchange Notes due 2014 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage										6.75%
Debt Conversion, Original Debt, Interest Rate of Debt										5.75%		3.75%
Debt Conversion, Original Debt, Amount											$ 107,530,000
Debt Conversion, Converted Instrument, Shares Issued | shares											8,867,443
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt											$ 107,530,000
Acceleration of interest expense related to debt conversion											1,526,000
Interest expense associated with embedded derivatives										$ 0	13,570,000	$ 11,799,000
Convertible Debt [Member] | 7.5% Senior Convertible Debentures [Member]
Debt Instrument [Line Items]
Interest rate effective percentage								7.50%
Principal Amount Of Debt Sold								$ 230,000,000
Proceeds from issuance of debt								$ 218,900,000
Debt Conversion, Original Debt, Interest Rate of Debt								2.50%
Debt Instrument, Convertible, Conversion Price | $ / shares								$ 15.98
Note conversion, net of income taxes (in shares) | shares								62.5743
Debt Instrument, Convertible, Conversion Basis Amount										1,000,000
Debt Instrument, Percent of Principal			100.00%
Interest expense associated with embedded derivatives										$ 8,777,000	5,553,000	3,614,000
Convertible Debt [Member] | 5.5% Variable Interest Senior Convertible Debentures due 2020 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage			5.50%							5.50%
Interest Rate			1.75%
Face amount			$ 258,750,000
Proceeds from issuance of debt			$ 250,300,000
Debt Instrument, Convertible, Conversion Price | $ / shares			$ 24.64
Debt Instrument, Convertible, Conversion Basis Amount			$ 1,000
Debt Instrument, Percent of Principal			100.00%
Long-term Debt										$ 172,614,000	159,919,000
Debt Instrument, Convertible, Conversion Basis Shares | shares			40.5891
Interest expense associated with embedded derivatives										$ 9,752,000	6,851,000	$ 0
Convertible Debt [Member] | 7.5% Variable Interest Senior Convertible Notes due 2019 [Member]
Debt Instrument [Line Items]
Interest rate effective percentage										7.50%
Long-term Debt										$ 97,881,000	$ 83,366,000
Convertible Debt [Member] | Executive Vice President [Member] | 6.75% Variable Interest Senior Convertible Note Due 2014 [Member]
Debt Instrument [Line Items]
Stock Ownership In Company Percentage						11.70%