Derivatives and Hedging Activities (Details) $ in Thousands	Sep. 30, 2016 USD ($) derivative	Dec. 31, 2015 USD ($) derivative
Asset Derivatives
Total derivatives (interest-rate products) not designated as hedging instruments	$ 24,790	$ 8,656
Liability Derivatives
Total derivatives (interest-rate products) not designated as hedging instruments	24,790	8,781
Posted collateral	$ 37,300	$ 14,700
Derivatives not designated as hedging instruments | Interest-rate swaps
Derivatives and Hedging Activities
Number of interest-rate swaps | derivative	107	64
Notional amount of interest-rate swaps	$ 747,200	$ 490,600
Derivatives not designated as hedging instruments | Interest-rate products
Asset Derivatives
Total derivatives (interest-rate products) not designated as hedging instruments	24,790	8,656
Liability Derivatives
Total derivatives (interest-rate products) not designated as hedging instruments	$ 24,790	$ 8,781