Financial Derivatives (Interest Rate Swaps) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Fixed payer interest rate swaps
Derivative [Line Items]
Notional Amount	$ (563,924)
Fair Value	$ (3,952)
Pay Rate	2.41%
Receive Rate	2.68%
Remaining Years to Maturity	5 years 179 days
Fixed payer interest rate swaps | 2020 [Member]
Derivative [Line Items]
Notional Amount	$ (68,607)
Fair Value	$ 549
Pay Rate	1.74%
Receive Rate	2.61%
Remaining Years to Maturity	1 year
Fixed payer interest rate swaps | 2021 [Member]
Derivative [Line Items]
Notional Amount	$ (121,499)
Fair Value	$ (603)
Pay Rate	2.71%
Receive Rate	2.63%
Remaining Years to Maturity	1 year 299 days
Fixed payer interest rate swaps | 2023 [Member]
Derivative [Line Items]
Notional Amount	$ (101,012)
Fair Value	$ 858
Pay Rate	2.06%
Receive Rate	2.66%
Remaining Years to Maturity	4 years 15 days
Fixed payer interest rate swaps | 2024 [Member]
Derivative [Line Items]
Notional Amount	$ (77,700)
Fair Value	$ (1,021)
Pay Rate	2.58%
Receive Rate	2.76%
Remaining Years to Maturity	4 years 296 days
Fixed payer interest rate swaps | 2025 [Member]
Derivative [Line Items]
Notional Amount	$ (30,023)
Fair Value	$ 296
Pay Rate	2.09%
Receive Rate	2.64%
Remaining Years to Maturity	6 years 245 days
Fixed payer interest rate swaps | 2026 [Member]
Derivative [Line Items]
Notional Amount	$ (10,200)
Fair Value	$ 191
Pay Rate	2.02%
Receive Rate	2.67%
Remaining Years to Maturity	7 years 161 days
Fixed payer interest rate swaps | 2028 [Member]
Derivative [Line Items]
Notional Amount	$ (69,602)
Fair Value	$ (1,975)
Pay Rate	2.71%
Receive Rate	2.68%
Remaining Years to Maturity	9 years 91 days
Fixed payer interest rate swaps | 2029 [Member]
Derivative [Line Items]
Notional Amount	$ (70,000)
Fair Value	$ (1,825)
Pay Rate	2.70%
Receive Rate	2.77%
Remaining Years to Maturity	9 years 292 days
Fixed payer interest rate swaps | 2030 [Member]
Derivative [Line Items]
Notional Amount	$ (685)
Fair Value	$ 2
Pay Rate	2.38%
Receive Rate	2.68%
Remaining Years to Maturity	11 years 237 days
Fixed payer interest rate swaps | 2045 [Member]
Derivative [Line Items]
Notional Amount	$ (7,896)
Fair Value	$ 19
Pay Rate	2.54%
Receive Rate	2.63%
Remaining Years to Maturity	26 years 252 days
Fixed payer interest rate swaps | 2049 [Member]
Derivative [Line Items]
Notional Amount	$ (6,700)
Fair Value	$ (443)
Pay Rate	2.89%
Receive Rate	2.80%
Remaining Years to Maturity	29 years 285 days
Fixed receiver interest rate swaps
Derivative [Line Items]
Notional Amount	$ (263,309)
Fair Value	$ 1,768
Pay Rate, Basis Swap	2.47%
Receive Rate, Basis Swap	2.34%
Remaining Years to Maturity	6 years 131 days
Fixed receiver interest rate swaps | 2021 [Member]
Derivative [Line Items]
Notional Amount	$ (5,928)
Fair Value	$ (21)
Pay Rate, Basis Swap	2.61%
Receive Rate, Basis Swap	2.00%
Remaining Years to Maturity	2 years 77 days
Fixed receiver interest rate swaps | 2022 [Member]
Derivative [Line Items]
Notional Amount	$ (53,974)
Fair Value	$ (761)
Pay Rate, Basis Swap	2.63%
Receive Rate, Basis Swap	1.85%
Remaining Years to Maturity	2 years 336 days
Fixed receiver interest rate swaps | 2023 [Member]
Derivative [Line Items]
Notional Amount	$ (48,657)
Fair Value	$ (509)
Pay Rate, Basis Swap	2.62%
Receive Rate, Basis Swap	2.00%
Remaining Years to Maturity	4 years 4 days
Fixed receiver interest rate swaps | 2024 [Member]
Derivative [Line Items]
Notional Amount	$ (68,500)
Fair Value	$ 816
Pay Rate, Basis Swap	2.38%
Receive Rate, Basis Swap	2.56%
Remaining Years to Maturity	4 years 292 days
Fixed receiver interest rate swaps | 2029 [Member]
Derivative [Line Items]
Notional Amount	$ (79,550)
Fair Value	$ 1,800
Pay Rate, Basis Swap	2.30%
Receive Rate, Basis Swap	2.66%
Remaining Years to Maturity	9 years 299 days
Fixed receiver interest rate swaps | 2049 [Member]
Derivative [Line Items]
Notional Amount	$ (6,700)
Fair Value	$ 443
Pay Rate, Basis Swap	2.80%
Receive Rate, Basis Swap	2.89%
Remaining Years to Maturity	29 years 285 days
Basis swaps
Derivative [Line Items]
Notional Amount	$ (12,900)
Fair Value	$ 4
Pay Rate, Basis Swap	2.61%
Receive Rate, Basis Swap	2.64%
Remaining Years to Maturity	77 days
Basis swaps | 2019 [Member]
Derivative [Line Items]
Notional Amount	$ (12,900)
Fair Value	$ 4
Pay Rate, Basis Swap	2.61%
Receive Rate, Basis Swap	2.64%
Remaining Years to Maturity	77 days