Subsequent events- Additional Information (Detail) (USD $)										3 Months Ended
	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2014 Segment, Discontinued Operations [Member]	Sep. 30, 2014 PUERTO RICO	Dec. 31, 2013 PUERTO RICO	Sep. 30, 2014 PNA Holding Co.	Dec. 31, 2013 PNA Holding Co.	Sep. 30, 2014 Subsequent Event Member California region sale of November 8, 2014 [Member] Segment, Discontinued Operations [Member]	Sep. 30, 2014 Subsequent Event Member California region sale of November 8, 2014 [Member] Indemnification Guarantee Member Segment, Discontinued Operations [Member]
Subsequent Events [Line Items]
Branches Sold									20
Loans held-for-sale	$ 178,008,000	[1]	$ 110,426,000	$ 1,099,673,000			$ 0	$ 0	$ 1,100,000,000
Deposits	24,466,105,000		26,711,145,000	1,089,046,000	19,995,426,000	19,730,408,000	0	0	1,100,000,000
Maximum Amount Of Future Payments Under Guarantee Percentage										1.5
Guarantee Obligations Term										two years
GuaranteeObligationsOriginAndPurpose										The Corporation also agreed to indemnify the purchaser for up to 1.5% of credit losses on transferred loans for a period of two years after the closing. Pursuant to this indemnification provision, the Corporation’s maximum exposure is approximately $16 million.
Maximum Amount Of Future Payments Under Gurantee										16,000,000
Net Premium On Sale Of California Operations									$ 4,000,000

[1] Loans held-for-sale from discontinued operations are presented as part of "Assets from Discontinued Operations" in the Consolidated Statement of Condition. Refer to Note 3 to the consolidated financial statements for further information on the discontinued operations.