Net Income (Loss) per Common Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended						12 Months Ended			15 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Sep. 30, 2012
Computation of basic and diluted net income (loss) per common share
Net income (loss) applicable to common shares	$ 26,828	$ 14,859	$ 12,039	$ 8,237	$ 2,558	$ 137	$ 61,963	$ 23,422	$ (38,774)	$ 12,013	$ 8,714
Weighted average number of common shares outstanding							155,801	154,811	144,278
Weighted average number of diluted common shares outstanding							162,765	156,090	144,278
Basic net income (loss) per share	$ 0.17	$ 0.10	$ 0.08	$ 0.05	$ 0.02	$ 0.00	$ 0.40	$ 0.15	$ (0.27)	$ 0.08	$ 0.06
Diluted net income (loss) per share	$ 0.17	$ 0.09	$ 0.08	$ 0.05	$ 0.02	$ 0.00	$ 0.39	$ 0.15	$ (0.27)	$ 0.08	$ 0.06
Stock Award One [Member]
Computation of basic and diluted net income (loss) per common share
Effect of dilutive stock awards							899	1,279	0
Stock Award Two [Member]
Computation of basic and diluted net income (loss) per common share
Effect of dilutive stock awards							6,065	0	0
Series D Preferred Stock [Member]
Computation of basic and diluted net income (loss) per common share
Income impact of assumed Series D Preferred Stock conversion							1,352	0	0
Net income after assumed Series D Preferred Stock conversion							$ 63,315	$ 23,422	$ (38,774)