Consolidated Statements of Stockholders' Equity (Deficit) Statement (USD $)	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Series 2012 Notes [Member]	Series 2012 Notes [Member] Additional Paid-in Capital [Member]	February 2018 Notes [Member]	February 2018 Notes [Member] Additional Paid-in Capital [Member]
Beginning Balance at Dec. 31, 2011	$ (204,273,000)		$ 1,397,000	$ (161,750,000)	$ (42,035,000)	$ (1,885,000)
Beginning Balance (in shares) at Dec. 31, 2011			139,679,752
Issuance of common stock under employee benefit plans (in Shares)			136,507
Issuance of common stock under employee benefit plans	0		(1,000)	(1,000)
Issuance of convertible debt	10,692,000			10,692,000
Stock-based compensation expense	937,000			937,000
Dividends declared, APIC adjustment	(83,944,000)			(83,944,000)
Statement of Comprehensive Income [Abstract]
Net income	211,669,000				211,669,000
Change in unrealized gains (losses) on available-for-sale securities, net of tax	(14,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	(22,000)	[1]				(22,000)
Changes in unrealized gains and losses on cash flow hedges, net of tax	(3,181,000)	[2]				(3,181,000)
Total comprehensive income	208,466,000
Ending Balance at Dec. 31, 2012	(68,122,000)		1,398,000	(234,066,000)	169,634,000	(5,088,000)
Ending Balance (in shares) at Dec. 31, 2012			139,816,259
Issuance of common stock under employee benefit plans (in Shares)			118,310
Issuance of common stock under employee benefit plans	0		(1,000)	(1,000)
Stock-based compensation expense	872,000			872,000
Tax benefit (expense) from employee stock options	22,000			22,000
Dividends declared, Retained Earnings adjustment	(84,013,000)				(84,013,000)
Statement of Comprehensive Income [Abstract]
Net income	264,530,000				264,530,000
Change in unrealized gains (losses) on available-for-sale securities, net of tax	1,122,000
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	1,122,000	[1]				1,122,000
Changes in unrealized gains and losses on cash flow hedges, net of tax	(922,000)	[2]				(922,000)
Total comprehensive income	264,730,000
Ending Balance at Dec. 31, 2013	113,489,000		1,399,000	(233,173,000)	350,151,000	(4,888,000)
Ending Balance (in shares) at Dec. 31, 2013			139,934,569
Issuance of common stock under employee benefit plans (in Shares)			148,882
Issuance of common stock under employee benefit plans	0		(2,000)	(2,000)
Stock Issued During Period, Shares, Conversion of Convertible Securities	22,103,031
Stock Issued During Period, Value, Conversion of Convertible Securities	221,000
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature	0			(221,000)
Issuance of convertible debt	102,134,000						10,900,000	102,134,000	18,689,000	18,689,000
Purchase of purchased call options, net of tax	20,118,000			20,118,000
Proceeds from the sale of warrants	11,427,000								11,427,000
Stock-based compensation expense	1,501,000			1,501,000
Tax benefit (expense) from employee stock options	(111,000)			(111,000)
Dividends declared, Retained Earnings adjustment	(96,655,000)				(96,655,000)
Statement of Comprehensive Income [Abstract]
Net income	322,244,000				322,244,000
Change in unrealized gains (losses) on available-for-sale securities, net of tax	(745,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	(765,000)	[1]				(765,000)
Changes in unrealized gains and losses on cash flow hedges, net of tax	8,602,000	[2]				8,602,000
Total comprehensive income	330,081,000
Ending Balance at Dec. 31, 2014	$ 460,437,000		$ 1,622,000	$ (119,874,000)	$ 575,740,000	$ 2,949,000
Ending Balance (in shares) at Dec. 31, 2014			162,186,482

[1] Net of tax of ($412), $604 and ($12) for the years ended December 31, 2014, 2013 and 2012, respectively.

[2] Net of tax of $4,632, ($496) and ($1,713) for the years ended December 31, 2014, 2013 and 2012, respectively.