Long-Term Borrowings (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Less: debt issurance costs	$ (3,193)	$ (3,486)	$ (3,581)
Long-term borrowings	216,807	216,514	216,419
Subordinated Notes, 5.75% [Member]
Subordinated notes	70,000	70,000	70,000
Subordinated Notes, 5.0% [Member]
Subordinated notes	$ 150,000	$ 150,000	$ 150,000