Earnings Per Common Share (Earnings Per Share Basic And Diluted) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Net income allocated to common shareholders	$ 43,734	$ 40,625	$ 82,965	$ 78,948
Less: Dividends to participating shares	(56)	(44)	(88)	(64)
Income allocated to participating shares	(129)	(160)	(247)	(320)
Net income allocated to common shareholders	$ 43,549	$ 40,421	$ 82,630	$ 78,564
Weighted average common shares outstanding - basic	89,645	87,291	87,585	87,254
Stock options and restricted stock (in shares)	290	252	308	274
Weighted average common shares outstanding - diluted	90,087	91,543	89,953	91,669
Earnings per common share, Basic (in dollars per share)	$ 0.49	$ 0.46	$ 0.94	$ 0.90
Earnings per common share, Diluted (in dollars per share)	$ 0.48	$ 0.44	$ 0.92	$ 0.86
Warrants - Series A1 And A2 [Member]
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Warrants (in shares)	0	3,908	1,917	4,031
Warrants - other [Member]
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Warrants (in shares)	152	92	143	110