Activity in Allowance for Losses for Non-Covered Loans and Covered Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment		$ 26
Allowance for Loan Losses, Collectively evaluated for impairment	$ 145,196	139,831
Allowance for Loan Losses	178,519	185,338
Acquired loans with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, other	33,323	45,481
Mortgage Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment		26
Allowance for Loan Losses, Collectively evaluated for impairment	122,712	122,590
Allowance for Loan Losses	137,295	146,154
Mortgage Receivable | Acquired loans with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, other	14,583	23,538
Other loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Collectively evaluated for impairment	22,484	17,241
Allowance for Loan Losses	41,224	39,184
Other loans | Acquired loans with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, other	$ 18,740	$ 21,943