Loans, Allowance for Loan and Lease Losses, and Reserve for Off-Balance Sheet Credit Commitments (Detail 3) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Changes in Accretable Yield for Acquired Impaired Loans
Balance at the beginning of the period	$ 168,469	$ 219,018
Accretion	(19,235)	(24,907)
Reclassification from nonaccretable difference	12,710	18,965
Disposals and other	(17,000)	(16,198)
Balance at the end of the period	$ 144,944	$ 196,878
Charge off of consumer loans, delinquency period for overdrafts, low end of range	60 days
Charge off of consumer loans, delinquency period for secured consumer loans	180 days