Derivatives, Hedging Activities, and Other Financial Instruments - Notional and Fair Value of Derivatives Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Other assets
Derivative [Line Items]
Derivative asset, notional amount	$ 120,244	$ 59,305
Credit risk derivative asset, fair value	6,989	1,722
Other liabilities
Derivative [Line Items]
Derivative liability, notional amount	120,244	59,305
Credit risk derivative liability, fair value	$ 7,274	$ 1,813