Derivatives (Foreign Exchange Derivative) (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative assets	$ 81,456,000	$ 66,146,000
Derivative liabilities	114,542,000	74,935,000
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional Amount	12,295,137,000	10,153,108,000
Derivative assets	79,140,000	66,146,000
Derivative liabilities	105,895,000	68,136,000
Derivatives not designated as hedging instruments | Foreign exchange forwards, spot and swaps
Derivative [Line Items]
Notional Amount	959,645,000	770,215,000
Derivative assets	9,408,000	5,840,000
Derivative liabilities	11,281,000	10,170,000
Derivatives not designated as hedging instruments | Customer Counterparties
Derivative [Line Items]
Derivative assets	3,628
Derivative liabilities	271
Derivatives not designated as hedging instruments | Customer Counterparties | Foreign exchange forwards, spot and swaps
Derivative [Line Items]
Notional Amount	372,470,000	167,707,000
Derivative assets	5,300,000	2,189,000
Derivative liabilities	4,652,000	850,000
Derivatives not designated as hedging instruments | Customer Counterparties | Forwards and spot
Derivative [Line Items]
Notional Amount	353,439,000	163,389,000
Derivative assets	5,298,000	2,189,000
Derivative liabilities	3,778,000	752,000
Derivatives not designated as hedging instruments | Customer Counterparties | Swaps
Derivative [Line Items]
Notional Amount	19,031,000	4,318,000
Derivative assets	2,000	0
Derivative liabilities	874,000	98,000
Derivatives not designated as hedging instruments | Financial Counterparties
Derivative [Line Items]
Derivative assets	0
Derivative liabilities	2,888
Derivatives not designated as hedging instruments | Financial Counterparties | Foreign exchange forwards, spot and swaps
Derivative [Line Items]
Notional Amount	587,175,000	602,508,000
Derivative assets	4,108,000	3,651,000
Derivative liabilities	6,629,000	9,320,000
Derivatives not designated as hedging instruments | Financial Counterparties | Forwards and spot
Derivative [Line Items]
Notional Amount	77,152,000	155,872,000
Derivative assets	47,000	662,000
Derivative liabilities	462,000	7,800,000
Derivatives not designated as hedging instruments | Financial Counterparties | Swaps
Derivative [Line Items]
Notional Amount	510,023,000	446,636,000
Derivative assets	4,061,000	2,989,000
Derivative liabilities	$ 6,167,000	$ 1,520,000