Investment Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized cost, Due in one year or less	$ 5,203	$ 6,849
Amortized cost, Due in one to five	7,486	44,108
Amortized cost, Due in five to ten years	37,340	29,964
Amortized cost, Due in over ten years	56,147	32,692
Amortized cost, Total	106,176	113,613
Total debt securities, Amortized cost	535,332	637,754
Fair value, Due in one year or less	5,206	6,886
Fair value, Due in one to five	7,608	44,358
Fair value, Due in five to ten years	39,790	31,927
Fair value, Due in over ten years	58,515	34,959
Fair value, Total	111,119	118,130
Total debt securities, Fair value	544,683	640,503
Mortgage-backed Securities - Residential
Schedule Of Available For Sale Securities [Line Items]
Total debt securities, Amortized cost	429,156	524,141
Total debt securities, Fair value	$ 433,564	$ 522,373