Deposits (Summary of Time Deposits Based Upon Contractual Maturity) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Three months or less	$ 356,446	$ 746,835
Over 3 months through 6 months	259,097	554,740
Over 6 months through 12 months	583,209	1,014,949
Over 12 months through 24 months	373,283	309,848
Over 24 months through 36 months	111,599	52,879
Over 36 months through 48 months	43,967	54,678
Over 48 months through 60 months	19,278	43,550
Thereafter	5,839	7,117
Total time deposits	$ 1,752,718	$ 2,784,596
Three months or less, Weighted Average Rate	0.78%	1.30%
Over 3 months through 6 months, Weighted Average Rate	0.68%	1.15%
Over 6 months through 12 months, Weighted Average Rate	0.67%	1.23%
Over 12 months through 24 months, Weighted Average Rate	0.88%	1.58%
Over 24 months through 36 months, Weighted Average Rate	1.77%	2.01%
Over 36 months through 48 months, Weighted Average Rate	1.83%	2.65%
Over 48 months through 60 months, Weighted Average Rate	1.44%	1.89%
Thereafter, Weighted Average Rate	2.32%	2.77%
Total time deposits, Weighted Average Rate	0.85%	1.33%