Fair Value (Carrying Amounts and Estimated Fair Values of Company's Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial Assets:
Interest-bearing Time Deposits with Banks	$ 745	$ 1,241
Financial Liabilities:
Time Deposits	(377,426)	(494,452)
Level 1
Financial Assets:
Cash and Short-term Investments	54,617	57,972
Interest-bearing Time Deposits with Banks	0	0
Loans, Net	0	0
Accrued Interest Receivable	0	0
Financial Liabilities:
Demand, Savings, and Money Market Deposits	(4,215,525)	(3,612,078)
Time Deposits	0	0
Short-term Borrowings	0	0
Long-term Debt	0	0
Accrued Interest Payable	0	0
Level 2
Financial Assets:
Cash and Short-term Investments	394,126	287,776
Interest-bearing Time Deposits with Banks	745	1,241
Loans, Net	0	0
Accrued Interest Receivable	8,362	6,137
Financial Liabilities:
Demand, Savings, and Money Market Deposits	0	0
Time Deposits	(376,922)	(495,171)
Short-term Borrowings	(52,591)	(52,905)
Long-term Debt	(79,221)	(88,342)
Accrued Interest Payable	(1,093)	(1,049)
Level 3
Financial Assets:
Cash and Short-term Investments	0	0
Interest-bearing Time Deposits with Banks	0	0
Loans, Net	2,962,916	3,032,690
Accrued Interest Receivable	11,640	14,141
Financial Liabilities:
Demand, Savings, and Money Market Deposits	0	0
Time Deposits	0	0
Short-term Borrowings	0	0
Long-term Debt	(54,144)	(54,960)
Accrued Interest Payable	(33)	(35)
Carrying Value
Financial Assets:
Cash and Short-term Investments	448,743	345,748
Interest-bearing Time Deposits with Banks	745	1,241
Loans, Net	2,960,180	3,026,340
Accrued Interest Receivable	20,002	20,278
Financial Liabilities:
Demand, Savings, and Money Market Deposits	(4,215,525)	(3,612,078)
Time Deposits	(377,426)	(494,452)
Short-term Borrowings	(52,591)	(52,905)
Long-term Debt	(133,799)	(141,624)
Accrued Interest Payable	(1,126)	(1,084)
Total
Financial Assets:
Cash and Short-term Investments	448,743	345,748
Interest-bearing Time Deposits with Banks	745	1,241
Loans, Net	2,962,916	3,032,690
Accrued Interest Receivable	20,002	20,278
Financial Liabilities:
Demand, Savings, and Money Market Deposits	(4,215,525)	(3,612,078)
Time Deposits	(376,922)	(495,171)
Short-term Borrowings	(52,591)	(52,905)
Long-term Debt	(133,365)	(143,302)
Accrued Interest Payable	$ (1,126)	$ (1,084)