Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Time certificates of deposit least amount	$ 100,000	$ 100,000
Held to Maturity, Fair Value, Total	875,306,000	752,177,000
Debt Securities, Available-for-sale, Amortized Cost	$ 1,425,392,000	$ 395,453,000
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	1,000,000	1,000,000
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	75,000,000	75,000,000
Common Stock, Shares, Outstanding	33,043,812	32,965,692
Common Stock, unvested restricted Stock awards	135,485	135,205
Shares Held in Rabbi Trust	84,207	84,126
Common Stock Outstanding
Common Stock, Shares, Outstanding	33,043,812	32,965,692
Subordinated Debt [Member]
Unamortized Debt Issuance Expense	$ 233,000	$ 304,000
Long-term Debt [Member]
Unamortized Debt Issuance Expense	$ 0	$ 40,000