Investment Securities - Summary of Available for Sale Securities With Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months Unrealized Losses	$ (415)	$ (422)
Less than Twelve Months Estimated Fair Value	37,867	26,695
Twelve Months or More Unrealized Losses	(63)	(90)
Twelve Months or More Estimated Fair Value	2,105	2,504
Total Unrealized Losses	(478)	(512)
Total Estimated Fair Value	39,972	29,199
Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months Unrealized Losses	(100)	(136)
Less than Twelve Months Estimated Fair Value	4,957	5,317
Total Unrealized Losses	(100)	(136)
Total Estimated Fair Value	4,957	5,317
Government Sponsored Agencies
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months Unrealized Losses	(255)	(221)
Less than Twelve Months Estimated Fair Value	26,916	16,231
Twelve Months or More Unrealized Losses	(63)	(90)
Twelve Months or More Estimated Fair Value	2,105	2,504
Total Unrealized Losses	(318)	(311)
Total Estimated Fair Value	29,021	18,735
Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Less than Twelve Months Unrealized Losses	(60)	(65)
Less than Twelve Months Estimated Fair Value	5,994	5,147
Total Unrealized Losses	(60)	(65)
Total Estimated Fair Value	$ 5,994	$ 5,147