Summary of Significant Accounting Policies - Corporate Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Premises and equipment
Depreciation	$ 2,570	$ 2,510	$ 2,740
Building | Minimum
Premises and equipment
Property, Plant and Equipment, Useful Life	10 years
Building | Maximum
Premises and equipment
Property, Plant and Equipment, Useful Life	40 years
Equipment, Furniture and Fixtures | Minimum
Premises and equipment
Property, Plant and Equipment, Useful Life	3 years
Equipment, Furniture and Fixtures | Maximum
Premises and equipment
Property, Plant and Equipment, Useful Life	10 years