Investment Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Amortized cost, Due in one year or less	$ 7,798	$ 9,290
Amortized cost, Due in one to five years	32,299	25,520
Amortized cost, Due in five to ten years	23,761	31,122
Amortized cost, Due in over ten years	67,426	62,909
Amortized cost, Total	131,284	128,841
Total debt securities, Amortized cost	547,295	579,715
Fair value, Due in one year or less	7,870	9,352
Fair value, Due in one to five years	33,470	26,340
Fair value, Due in five to ten years	24,748	32,248
Fair value, Due in over ten years	67,910	61,725
Fair value, Total	133,998	129,665
Total debt securities, Fair value	544,706	573,573
Mortgage-backed Securities - Residential
Schedule Of Available For Sale Securities [Line Items]
Total debt securities, Amortized cost	416,011	450,874
Total debt securities, Fair value	$ 410,708	$ 443,908