Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Consolidated Balance Sheets Parenthetical [Abstract]
Debt securities, available-for-sale, cost (in dollars)	$ 530,516	$ 550,268
Equity securities, available for sale, cost (in dollars)	68,709	68,709
Other investments, cost	3,763	3,763
Subordinated debt securities, unamortized debt issuance cost (in dollars)	$ 872	$ 898
Common stock, par value (in dollars per share)	$ 0.18	$ 0.18
Common stock, authorized shares	33,333,333	33,333,333
Common stock, issued shares	20,872,831	20,872,831
Treasury stock, shares	2,749,738	2,846,131