Composition of loans held-in-portfolio-noncovered loans (Detail) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio	[1]	$ 22,435,145	$ 19,404,451
Commercial Multi Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		663,100	487,280
Commercial Real Estate Non Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		3,445,267	2,526,146
Commercial Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		2,177,604	1,667,267
Commercial And Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		3,718,745	3,453,574
Commercial Real Estate Construction Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		696,010	251,820
Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		7,225,823	6,502,886
Finance Leases Portfolio Segment Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		592,816	564,389
Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio	[2]	72,502	80,818
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		3,843,278	3,870,271
Consumer [Member] | Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		1,152,367	1,155,229
Consumer [Member] | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		340,785	366,162
Consumer [Member] | Personal [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		1,352,343	1,375,452
Consumer [Member] | Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		799,843	767,369
Consumer [Member] | Consumer Other Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered Loans held-in-portfolio		$ 197,940	$ 206,059

[1] Non-covered loans held-in-portfolio at June 30, 2015 are net of $100 million in unearned income and exclude $202 million in loans held-for-sale. (December 31, 2014 - $94 million in unearned income and $106 million in loans held-for-sale.)

[2] The legacy portfolio is comprised of commercial loans, construction loans and lease financings related to certain lending products exited by the Corporation as part of restructuring efforts carried out in prior years at the BPNA segment.