Earnings Per Common Share (Earnings Per Share Basic And Diluted) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Net income allocated to common shareholders	$ 44,666	$ 44,378	$ 127,631	$ 123,326
Dividends Participating Shares	(48)	(37)	(137)	(102)
Income allocated to participating shares	(114)	(149)	(360)	(470)
Net income allocated to common shareholders	$ 44,504	$ 44,192	$ 127,134	$ 122,754
Weighted average common shares outstanding - basic	89,759	87,394	88,318	87,301
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	451	260	406	281
Weighted-average common shares outstanding - diluted	90,423	91,884	90,193	91,754
Earnings per common share, Basic (in dollars per share)	$ 0.50	$ 0.51	$ 1.44	$ 1.41
Earnings per common share, Diluted (in dollars per share)	$ 0.49	$ 0.48	$ 1.41	$ 1.34
Warrants - Series A1 And A2 [Member]
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Warrants (in shares)	0	4,114	1,300	4,060
Warrants - other [Member]
Earnings Per Share Basic And Diluted By Common Class [Line Items]
Warrants (in shares)	213	116	169	112