Derivatives (Details 2) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017 USD ($) company	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Derivative liabilities	$ 83,400	$ 82,323
Derivative assets	79,764	83,780
Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	42,566	131,391
Derivative liabilities	6,686	5,976
Derivative assets	0	4,325
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	9,723,734	8,507,660
Derivative liabilities	76,714	76,347
Derivative assets	79,764	79,455
Interest rate swaps on certificates of deposit | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	42,566	48,365
Derivative liabilities	6,686	5,976
Derivative assets	0	0
Foreign currency forward contracts | Derivatives designated as hedging instruments
Derivative [Line Items]
Notional amount	0	83,026
Derivative liabilities	0	0
Derivative assets	0	4,325
Interest rate swaps and options | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	8,172,811	7,668,482
Derivative liabilities	63,551	65,131
Derivative assets	64,254	67,578
Notional amount of derivative assets	4,090,000	3,860,000
Notional amount of derivative liabilities	4,090,000	3,810,000
Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	1,481,244	767,764
Derivative liabilities	13,161	11,213
Derivative assets	14,722	11,874
RPAs | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	69,679	71,414
Derivative liabilities	2	3
Derivative assets	$ 2	$ 3
Weighted average remaining maturity (in years)	3 years 4 months	3 years 8 months
RPAs | Derivatives not designated as hedging instruments | Long
Derivative [Line Items]
Notional amount	$ 48,200	$ 48,300
Derivative liabilities	2	3
Interest rate derivative exposure	113	179
RPAs | Derivatives not designated as hedging instruments | Short
Derivative [Line Items]
Notional amount	21,400	23,100
Derivative assets	2	3
Warrants | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	0	0
Derivative liabilities	0	0
Derivative assets	$ 786	$ 0
Number of public companies in which warrants are held | company	4