Other Income and Other Expense - Other Income and Other Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other income:
Bank owned life insurance	$ 52,984	$ 50,004	$ 56,120
Credit-related fee income	81,558	72,454	72,271
Letter of credit fees	52,724	56,708	59,889
Gains from loan securitization transactions			63,066
Other expense:
Professional services	346,840	401,946	335,794
Amortization of capitalized servicing rights	49,906	$ 68,410	65,354
Advertising and promotion	$ 59,227		$ 56,597