Parent company financial statements - Condensed Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments in consolidated subsidiaries
Investment in Bayview Lending Group LLC	$ 93,000	$ 115,000
Other assets	4,448,779	4,611,773
Total assets	83,008,803	77,924,287
Liabilities
Accrued expenses and other liabilities	1,512,717	1,790,121
Long-term borrowings	4,607,758	6,686,226
Total liabilities	72,806,210	68,653,078
Shareholders' equity	10,202,593	9,271,209
Total liabilities and shareholders' equity	83,008,803	77,924,287
Parent Company [Member]
Assets
Cash in subsidiary bank	4,774	3,798
Due from consolidated bank subsidiaries
Money-market savings	714,677	645,330
Current income tax receivable	1,835
Total due from consolidated bank subsidiaries	716,512	645,330
Investments in consolidated subsidiaries
Banks and bank holding company	10,495,557	9,929,758
Other	16,344	16,025
Investments in unconsolidated subsidiaries (note 19)	33,916	34,091
Investment in Bayview Lending Group LLC	93,489	115,000
Other assets	83,975	82,358
Total assets	11,444,567	10,826,360
Liabilities
Due to consolidated bank subsidiaries	213	30
Accrued expenses and other liabilities	60,619	75,828
Long-term borrowings	1,181,142	1,479,293
Total liabilities	1,241,974	1,555,151
Shareholders' equity	10,202,593	9,271,209
Total liabilities and shareholders' equity	$ 11,444,567	$ 10,826,360