Derivatives and Hedging Activities (Customer Related Derivative Positions - Not Designated as Hedges) (Details) $ in Thousands	Sep. 30, 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	$ 822	$ 624
Not Designated as Hedging Instrument | Receive fixed, pay variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	238	222
Less than 1 year	$ 10,533	$ 30,245
Less than 2 years	73,428	21,708
Less than 3 years	68,458	63,771
Less than 4 years	177,864	165,783
Thereafter	575,721	567,897
Total	906,004	849,404
Fair Value	$ 11,271	$ 12,005
Not Designated as Hedging Instrument | Pay fixed, receive variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	223	207
Less than 1 year	$ 10,533	$ 30,245
Less than 2 years	73,428	21,708
Less than 3 years	68,458	63,771
Less than 4 years	177,864	165,783
Thereafter	575,721	567,897
Total	906,004	849,404
Fair Value	$ (11,272)	$ (12,008)
Not Designated as Hedging Instrument | Buys foreign currency, sells U.S. currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	17	33
Less than 1 year	$ 32,390	$ 45,711
Less than 2 years	3,780
Total	36,170	45,711
Fair Value	$ 1,683	$ (2,250)
Not Designated as Hedging Instrument | Buys U.S. currency, sells foreign currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	17	33
Less than 1 year	$ 32,390	$ 45,711
Less than 2 years	3,780
Total	36,170	45,711
Fair Value	$ (1,668)	$ 2,277