Financial Derivatives (Interest Rate Swaps) (Details) - Interest rate swaps - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Long
Derivative [Line Items]
Notional Amount	$ 434,364	$ 305,723
Fair Value	8,265	1,348
Long | 2021 [Member]
Derivative [Line Items]
Notional Amount	12,950	181,950
Fair Value	253	(49)
Long | 2022 [Member]
Derivative [Line Items]
Notional Amount	87,683	53,974
Fair Value	1,184	441
Long | 2023 [Member]
Derivative [Line Items]
Notional Amount	48,657	48,657
Fair Value	2,340	709
Long | 2024 [Member]
Derivative [Line Items]
Notional Amount	11,342	11,342
Fair Value	895	306
Long | 2025 [Member]
Derivative [Line Items]
Notional Amount	134,876
Fair Value	238
Long | 2027 [Member]
Derivative [Line Items]
Notional Amount	25,108
Fair Value	28
Long | 2029 [Member]
Derivative [Line Items]
Notional Amount	9,800	9,800
Fair Value	1,011	$ (59)
Long | 2030 [Member]
Derivative [Line Items]
Notional Amount	103,948
Fair Value	$ 2,316
Long | Weighted Average
Derivative [Line Items]
Pay Rate	1.08%	1.78%
Receive Rate	1.12%	1.91%
Remaining Years to Maturity	5 years 5 months 4 days	2 years 5 months 19 days
Long | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	1.75%	1.67%
Receive Rate	0.90%	1.89%
Remaining Years to Maturity	1 year 5 months 15 days	1 year 10 months 2 days
Long | Weighted Average | 2022 [Member]
Derivative [Line Items]
Pay Rate	1.33%	1.85%
Receive Rate	1.12%	1.91%
Remaining Years to Maturity	1 year 11 months 12 days	2 years 2 months 1 day
Long | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	2.00%	2.00%
Receive Rate	1.18%	1.92%
Remaining Years to Maturity	3 years 3 days	3 years 3 months 3 days
Long | Weighted Average | 2024 [Member]
Derivative [Line Items]
Pay Rate	2.33%	2.33%
Receive Rate	1.91%	2.09%
Remaining Years to Maturity	3 years 11 months 23 days	4 years 2 months 23 days
Long | Weighted Average | 2025 [Member]
Derivative [Line Items]
Pay Rate	0.55%
Receive Rate	1.22%
Remaining Years to Maturity	4 years 11 months 23 days
Long | Weighted Average | 2027 [Member]
Derivative [Line Items]
Pay Rate	0.63%
Receive Rate	0.00%
Remaining Years to Maturity	7 years 3 days
Long | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate	1.78%	1.78%
Receive Rate	1.51%	1.91%
Remaining Years to Maturity	9 years 6 months 7 days	9 years 9 months 7 days
Long | Weighted Average | 2030 [Member]
Derivative [Line Items]
Pay Rate	0.95%
Receive Rate	1.15%
Remaining Years to Maturity	9 years 11 months 12 days
Short
Derivative [Line Items]
Notional Amount	$ 696,360	$ 732,961
Fair Value	(31,959)	(4,599)
Short | 2020 [Member]
Derivative [Line Items]
Notional Amount	5,600	68,607
Fair Value	(28)	(234)
Short | 2021 [Member]
Derivative [Line Items]
Notional Amount	160,029	268,929
Fair Value	(2,788)	(419)
Short | 2022 [Member]
Derivative [Line Items]
Notional Amount	142,747	31,350
Fair Value	(1,854)	9
Short | 2023 [Member]
Derivative [Line Items]
Notional Amount	101,012	101,012
Fair Value	(5,098)	(1,265)
Short | 2024 [Member]
Derivative [Line Items]
Notional Amount		13,000
Fair Value		99
Short | 2025 [Member]
Derivative [Line Items]
Notional Amount	58,500	12,800
Fair Value	(887)	(24)
Short | 2026 [Member]
Derivative [Line Items]
Notional Amount	28,104	59,902
Fair Value	(1,264)	1,946
Short | 2028 [Member]
Derivative [Line Items]
Notional Amount	32,942	32,942
Fair Value	(4,688)	(1,634)
Short | 2029 [Member]
Derivative [Line Items]
Notional Amount	92,594	136,838
Fair Value	(9,600)	(2,018)
Short | 2030 [Member]
Derivative [Line Items]
Notional Amount	67,936	685
Fair Value	(2,563)	(32)
Short | 2036 [Member]
Derivative [Line Items]
Notional Amount	1,100	1,100
Fair Value	(108)	87
Short | 2049 [Member]
Derivative [Line Items]
Notional Amount	5,796	5,796
Fair Value	$ (3,081)	$ (1,114)
Short | Weighted Average
Derivative [Line Items]
Pay Rate	1.58%	1.83%
Receive Rate	1.30%	1.94%
Remaining Years to Maturity	4 years 8 months 4 days	4 years 3 months 21 days
Short | Weighted Average | 2020 [Member]
Derivative [Line Items]
Pay Rate	1.64%	1.74%
Receive Rate	1.23%	1.93%
Remaining Years to Maturity	2 months 26 days	2 months 26 days
Short | Weighted Average | 2021 [Member]
Derivative [Line Items]
Pay Rate	1.86%	1.73%
Receive Rate	1.52%	1.95%
Remaining Years to Maturity	1 year 3 months 3 days	1 year 7 months 20 days
Short | Weighted Average | 2022 [Member]
Derivative [Line Items]
Pay Rate	1.16%	1.65%
Receive Rate	1.40%	1.93%
Remaining Years to Maturity	1 year 10 months 24 days	2 years 1 month 20 days
Short | Weighted Average | 2023 [Member]
Derivative [Line Items]
Pay Rate	2.06%	2.06%
Receive Rate	1.20%	1.91%
Remaining Years to Maturity	3 years 14 days	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	0.82%
Receive Rate	0.22%
Remaining Years to Maturity	4 years 11 months 26 days	5 years 2 months 19 days
Short | Weighted Average | 2026 [Member]
Derivative [Line Items]
Pay Rate	1.25%	1.24%
Receive Rate	1.45%	1.94%
Remaining Years to Maturity	6 years 3 months	6 years 6 months
Short | Weighted Average | 2028 [Member]
Derivative [Line Items]
Pay Rate	2.40%	2.40%
Receive Rate	1.28%	1.93%
Remaining Years to Maturity	8 years 1 month 2 days	8 years 4 months 2 days
Short | Weighted Average | 2029 [Member]
Derivative [Line Items]
Pay Rate	1.78%	2.02%
Receive Rate	1.46%	1.96%
Remaining Years to Maturity	9 years 6 months 14 days	9 years 7 months 9 days
Short | Weighted Average | 2030 [Member]
Derivative [Line Items]
Pay Rate	1.10%	2.38%
Receive Rate	1.28%	1.90%
Remaining Years to Maturity	9 years 11 months 8 days	10 years 10 months 24 days
Short | Weighted Average | 2036 [Member]
Derivative [Line Items]
Pay Rate	1.45%	1.45%
Receive Rate	1.45%	1.94%
Remaining Years to Maturity	15 years 10 months 20 days	16 years 1 month 20 days
Short | Weighted Average | 2049 [Member]
Derivative [Line Items]
Pay Rate	2.89%	2.89%
Receive Rate	1.91%	2.09%
Remaining Years to Maturity	28 years 9 months 10 days	29 years 10 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%