Note Deposits (Total interest bearing deposits) (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Deposits Abstract
Savings accounts	$ 7,307,272	$ 7,010,391
NOW, money market abd other interest bearing demand deposits	5,957,465	5,632,449
Total savings, NOW, money market and other interest bearing demand deposits	13,264,737	12,642,840
Time Deposits Abstract
Under $100,000	3,798,028	4,014,359
$100,000 and over	4,079,735	4,151,009
Total certificates of deposit	7,877,763	8,165,368
Total interest bearing deposits	$ 21,142,500	$ 20,808,208