Long-Term Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Less: debt issurance costs	$ (2,997)	$ (3,095)
Long-term borrowings	217,003	216,905
Subordinated Notes, 5.75% [Member]
Subordinated notes	70,000	70,000
Subordinated Notes, 5.0% [Member]
Subordinated notes	$ 150,000	$ 150,000