Derivatives and Hedging Activities (Customer Related Derivative Positions - Not Designated as Hedges) (Details) - Not Designated as Hedging Instrument $ in Thousands		Mar. 31, 2019 USD ($) position	Dec. 31, 2018 USD ($) position
Receive fixed, pay variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	235	235
Less than 1 year		$ 70,141	$ 50,702
Less than 2 years		151,524	124,222
Less than 3 years		54,375	97,904
Less than 4 years		56,044	47,308
Thereafter		618,648	631,471
Total		950,732	951,607
Fair Value		$ 9,724	$ (2,907)
Pay fixed, receive variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	222	220
Less than 1 year		$ 70,141	$ 50,702
Less than 2 years		151,524	124,222
Less than 3 years		54,375	97,904
Less than 4 years		56,044	47,308
Thereafter		618,648	631,471
Total		950,732	951,607
Fair Value		$ (9,724)	$ 2,903
Buys foreign currency, sells U.S. currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	33	27
Less than 1 year		$ 70,994	$ 60,297
Less than 2 years			3,505
Total		70,994	63,802
Fair Value		$ (2,102)	$ (1,404)
Buys U.S. currency, sells foreign currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	33	27
Less than 1 year		$ 70,994	$ 60,297
Less than 2 years			3,505
Total		70,994	63,802
Fair Value		$ 2,140	$ 1,434

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