Computation of net income (loss) per common share ("EPS"), basic and diluted (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net Income	$ 327,468	$ 65,739	$ 207,161	$ 114,147
Preferred stock dividends	(931)	(930)	(1,861)	(1,861)
Preferred Stock Conversions Inducements	0	0	0	0
Net income (loss) applicable to common stock	$ 326,537	$ 64,809	$ 205,300	$ 112,286
Weighted Average Number Of Shares Outstanding Basic	102,620,295	102,295,113	102,642,329	102,318,459
Weighted Average Number Diluted Shares Outstanding Adjustment	297,052	115,505	315,407	161,071
Average common shares outstanding - assuming dilution	102,917,347	102,410,618	102,957,736	102,479,530
Earnings Per Share Basic	$ 3.18	$ 0.63	$ 2.00	$ 1.10
Earnings Per Share Diluted	$ 3.17	$ 0.63	$ 1.99	$ 1.10