CONSOLIDATED STATEMENTS OF CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Available-for-sale securities, at amortized cost	$ 1,363,902	$ 1,408,996
Securities - held-to-maturity	139,377	140,315
Equity securities, at amortized cost	$ 1,000	$ 1,000
Common Stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common Stock, authorized (in shares)	25,000,000	25,000,000
Common Stock, issued (in shares)	15,348,287	15,301,524
Treasury stock, shares (in shares)	(122,227)	(120,805)