Financial Derivatives (Interest Rate Swaps) (Details) - Interest rate swaps - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Long
Derivative [Line Items]
Notional Amount	$ 253,423	$ 305,723
Fair Value	8,329	1,348
Long | 2021 [Member]
Derivative [Line Items]
Notional Amount	12,950	181,950
Fair Value	205	(49)
Long | 2022 [Member]
Derivative [Line Items]
Notional Amount	103,974	53,974
Fair Value	1,413	441
Long | 2023 [Member]
Derivative [Line Items]
Notional Amount	48,657	48,657
Fair Value	2,209	709
Long | 2024 [Member]
Derivative [Line Items]
Notional Amount	86,342	11,342
Fair Value	4,567	306
Long | 2029 [Member]
Derivative [Line Items]
Notional Amount		9,800
Fair Value		$ (59)
Long | 2035
Derivative [Line Items]
Notional Amount	500
Fair Value	(14)
Long | 2040
Derivative [Line Items]
Notional Amount	500
Fair Value	(20)
Long | 2050
Derivative [Line Items]
Notional Amount	500
Fair Value	$ (31)
Long | Weighted Average
Derivative [Line Items]
Pay Rate	1.48%	1.78%
Receive Rate	0.22%	1.91%
Remaining Years to Maturity	2 years 5 months 23 days	2 years 5 months 19 days
Long | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	1.75%	1.67%
Receive Rate	0.24%	1.89%
Remaining Years to Maturity	8 months 15 days	1 year 10 months 2 days
Long | Weighted Average | 2022 [Member]
Derivative [Line Items]
Pay Rate	1.07%	1.85%
Receive Rate	0.22%	1.91%
Remaining Years to Maturity	1 year 5 months 23 days	2 years 2 months 1 day
Long | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	2.00%	2.00%
Receive Rate	0.24%	1.92%
Remaining Years to Maturity	2 years 3 months 3 days	3 years 3 months 3 days
Long | Weighted Average | 2024 [Member]
Derivative [Line Items]
Pay Rate	1.65%	2.33%
Receive Rate	0.22%	2.09%
Remaining Years to Maturity	3 years 8 months 23 days	4 years 2 months 23 days
Long | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate		1.78%
Receive Rate		1.91%
Remaining Years to Maturity		9 years 9 months 7 days
Long | Weighted Average | 2035
Derivative [Line Items]
Pay Rate	0.74%
Receive Rate	0.09%
Remaining Years to Maturity	14 years 9 months 21 days
Long | Weighted Average | 2040
Derivative [Line Items]
Pay Rate	0.84%
Receive Rate	0.09%
Remaining Years to Maturity	19 years 9 months 25 days
Long | Weighted Average | 2050
Derivative [Line Items]
Pay Rate	0.90%
Receive Rate	0.09%
Remaining Years to Maturity	29 years 9 months 25 days
Short
Derivative [Line Items]
Notional Amount	$ 408,295	$ 732,961
Fair Value	(14,984)	(4,599)
Short | 2020 [Member]
Derivative [Line Items]
Notional Amount		68,607
Fair Value		(234)
Short | 2021 [Member]
Derivative [Line Items]
Notional Amount	17,500	268,929
Fair Value	(231)	(419)
Short | 2022 [Member]
Derivative [Line Items]
Notional Amount	96,533	31,350
Fair Value	(1,535)	9
Short | 2023 [Member]
Derivative [Line Items]
Notional Amount	146,012	101,012
Fair Value	(4,770)	(1,265)
Short | 2024 [Member]
Derivative [Line Items]
Notional Amount		13,000
Fair Value		99
Short | 2025 [Member]
Derivative [Line Items]
Notional Amount	66,503	12,800
Fair Value	(1,034)	(24)
Short | 2027 [Member]
Derivative [Line Items]
Notional Amount	9,732
Fair Value	60
Short | 2026 [Member]
Derivative [Line Items]
Notional Amount	11,216	59,902
Fair Value	(458)	1,946
Short | 2028 [Member]
Derivative [Line Items]
Notional Amount	16,644	32,942
Fair Value	(2,169)	(1,634)
Short | 2029 [Member]
Derivative [Line Items]
Notional Amount	22,744	136,838
Fair Value	(2,289)	(2,018)
Short | 2030 [Member]
Derivative [Line Items]
Notional Amount	13,015	685
Fair Value	(369)	(32)
Short | 2035
Derivative [Line Items]
Notional Amount	500
Fair Value	15
Short | 2036 [Member]
Derivative [Line Items]
Notional Amount	1,100	1,100
Fair Value	(47)	87
Short | 2040
Derivative [Line Items]
Notional Amount	500
Fair Value	20
Short | 2049 [Member]
Derivative [Line Items]
Notional Amount	5,796	5,796
Fair Value	(2,208)	$ (1,114)
Short | 2050
Derivative [Line Items]
Notional Amount	500
Fair Value	$ 31
Short | Weighted Average
Derivative [Line Items]
Pay Rate	1.39%	1.83%
Receive Rate	0.23%	1.94%
Remaining Years to Maturity	3 years 9 months 25 days	4 years 3 months 21 days
Short | Weighted Average | 2020 [Member]
Derivative [Line Items]
Pay Rate		1.74%
Receive Rate		1.93%
Remaining Years to Maturity		2 months 26 days
Short | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	2.75%	1.73%
Receive Rate	0.24%	1.95%
Remaining Years to Maturity	2 months 19 days	1 year 7 months 20 days
Short | Weighted Average | 2022 [Member]
Derivative [Line Items]
Pay Rate	1.19%	1.65%
Receive Rate	0.22%	1.93%
Remaining Years to Maturity	1 year 1 month 20 days	2 years 1 month 20 days
Short | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	1.50%	2.06%
Receive Rate	0.23%	1.91%
Remaining Years to Maturity	2 years 5 months 1 day	3 years 3 months 14 days
Short | Weighted Average | 2024 [Member]
Derivative [Line Items]
Pay Rate		1.56%
Receive Rate		1.89%
Remaining Years to Maturity		4 years 10 months 24 days
Short | Weighted Average | 2025 [Member]
Derivative [Line Items]
Pay Rate	0.73%
Receive Rate	0.21%
Remaining Years to Maturity	4 years 9 months	5 years 2 months 19 days
Short | Weighted Average | 2027 [Member]
Derivative [Line Items]
Pay Rate	0.49%
Receive Rate	0.24%
Remaining Years to Maturity	6 years 5 months 23 days
Short | Weighted Average | 2026 [Member]
Derivative [Line Items]
Pay Rate	1.23%	1.24%
Receive Rate	0.25%	1.94%
Remaining Years to Maturity	5 years 6 months	6 years 6 months
Short | Weighted Average | 2028 [Member]
Derivative [Line Items]
Pay Rate	2.39%	2.40%
Receive Rate	0.24%	1.93%
Remaining Years to Maturity	7 years 3 months 25 days	8 years 4 months 2 days
Short | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate	1.94%	2.02%
Receive Rate	0.23%	1.96%
Remaining Years to Maturity	8 years 7 months 9 days	9 years 7 months 9 days
Short | Weighted Average | 2030 [Member]
Derivative [Line Items]
Pay Rate	1.13%	2.38%
Receive Rate	0.22%	1.90%
Remaining Years to Maturity	9 years 3 months 14 days	10 years 10 months 24 days
Short | Weighted Average | 2035
Derivative [Line Items]
Pay Rate	0.78%
Receive Rate	0.09%
Remaining Years to Maturity	14 years 9 months 21 days
Short | Weighted Average | 2036 [Member]
Derivative [Line Items]
Pay Rate	1.45%	1.45%
Receive Rate	0.25%	1.94%
Remaining Years to Maturity	15 years 1 month 17 days	16 years 1 month 20 days
Short | Weighted Average | 2040
Derivative [Line Items]
Pay Rate	0.90%
Receive Rate	0.09%
Remaining Years to Maturity	19 years 9 months 25 days
Short | Weighted Average | 2049 [Member]
Derivative [Line Items]
Pay Rate	2.89%	2.89%
Receive Rate	0.23%	2.09%
Remaining Years to Maturity	28 years 7 days	29 years 10 days
Short | Weighted Average | 2050
Derivative [Line Items]
Pay Rate	0.98%
Receive Rate	0.09%
Remaining Years to Maturity	29 years 9 months 25 days
Forward-starting interest rate swap [Member] | Short
Derivative [Line Items]
Notional Amount		$ 20,900
Fair Value		$ (41)
Derivative fixed interest rate including forward-starting swaps		1.83%