Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposit [Abstract]
Certificates of Deposit, CDARS	$ 517,500	$ 700,700
Non-interest-bearing demand	4,093,976	2,288,048
Time Deposit Maturities, Next Twelve Months	1,507,050
Time Deposit Maturities, Year Two	88,184
Time Deposit Maturities, Year Three	9,633
Time Deposit Maturities, Year Four	3,552
Time Deposit Maturities, Year Five	3,235
Time Deposits	1,611,654
Interest Bearing Deposit Demand	1,028,073	854,935
Deposits, Savings Deposits	5,296,921	3,869,699
Time Deposits, $250,000 or more	1,569,525	1,339,238
Time Deposits, Less than $250,000	42,129	579,123
Deposits	12,030,624	8,931,043
Deposits, ICS	714,400	481,200
Deposits, Wholesale	184,200	257,000
Brokered Deposits, Regulatory	$ 365,600	$ 202,400