Derivatives and Hedging Activities (Customer Related Derivative Positions - Not Designated as Hedges) (Details) $ in Thousands		Dec. 31, 2017 USD ($) position	Dec. 31, 2016 USD ($) position
Summary of customer related derivative positions, not designated as hedging
Total		$ 100,000	$ 75,000
Fair Value		$ 1,616	$ 624
Not Designated as Hedging Instrument [Member] | Receive fixed, pay variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions (1) | position	[1]	246	222
Less than 1 year		$ 36,023	$ 30,245
Less than 2 years		61,500	21,708
Less than 3 years		152,287	63,771
Less than 4 years		111,147	165,783
Thereafter		591,385	567,897
Total		952,342	849,404
Fair Value		$ 3,875	$ 12,005
Not Designated as Hedging Instrument [Member] | Pay fixed, receive variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions (1) | position	[1]	231	207
Less than 1 year		$ 36,023	$ 30,245
Less than 2 years		61,500	21,708
Less than 3 years		152,287	63,771
Less than 4 years		111,147	165,783
Thereafter		591,385	567,897
Total		952,342	849,404
Fair Value		$ (3,880)	$ (12,008)
Not Designated as Hedging Instrument [Member] | Buys foreign currency, sells U.S. currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions (1) | position	[1]	15	33
Less than 1 year		$ 26,382	$ 45,711
Less than 2 years		3,780
Total		30,162	45,711
Fair Value		$ 1,202	$ (2,250)
Not Designated as Hedging Instrument [Member] | Buys U.S. currency, sells foreign currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions (1) | position	[1]	15	33
Less than 1 year		$ 26,382	$ 45,711
Less than 2 years		3,780
Total		30,162	45,711
Fair Value		$ (1,188)	$ 2,277

[1] The Company may enter into one dealer swap agreement which offsets multiple commercial borrower swap agreements.