Derivative Instruments Fair Value and Offsets Table (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative Asset, Collateral, Obligation to Repay Cash, Offset	[1]		$ 45
Derivative Asset, Fair Value, Gross Asset		$ 5,444	4,639
Derivative Asset, Fair Value, Gross Liability		(1,159)	(984)
Derivative Asset, Fair Value, Amount Offset Against Collateral		4,285	3,655
Derivative Liability, Fair Value, Gross Liability		4,601	1,912
Derivative Liability, Fair Value, Gross Asset		(1,159)	(938)
Derivative Liability, Fair Value, Amount Offset Against Collateral		3,442	974
Financial Swaps | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		5,003	4,639
Derivative Asset, Fair Value, Gross Liability		(915)	(984)	[1]
Derivative Asset, Fair Value, Amount Offset Against Collateral		4,088	3,655
Derivative Liability, Fair Value, Gross Liability		915	938
Derivative Liability, Fair Value, Gross Asset		(915)	(938)
Derivative Liability, Fair Value, Amount Offset Against Collateral		0	0
Financial Swaps | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		173	0
Derivative Asset, Fair Value, Gross Liability		(173)	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		0	0
Derivative Liability, Fair Value, Gross Liability		2,940	806
Derivative Liability, Fair Value, Gross Asset		(173)	0
Derivative Liability, Fair Value, Amount Offset Against Collateral		2,767	806
Financial Swaps | Other Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset			0
Derivative Asset, Fair Value, Gross Liability			0
Derivative Asset, Fair Value, Amount Offset Against Collateral			0
Derivative Liability, Fair Value, Gross Liability			64
Derivative Liability, Fair Value, Gross Asset			0
Derivative Liability, Fair Value, Amount Offset Against Collateral			64
Financial Swaps | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		71
Derivative Asset, Fair Value, Gross Liability		(71)
Derivative Asset, Fair Value, Amount Offset Against Collateral		0
Derivative Liability, Fair Value, Gross Liability		746
Derivative Liability, Fair Value, Gross Asset		(71)
Derivative Liability, Fair Value, Amount Offset Against Collateral		675
Forward contracts | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset		197
Derivative Asset, Fair Value, Gross Liability		0
Derivative Asset, Fair Value, Amount Offset Against Collateral		197
Derivative Liability, Fair Value, Gross Liability		0
Derivative Liability, Fair Value, Gross Asset		0
Derivative Liability, Fair Value, Amount Offset Against Collateral		$ 0
Forward contracts | Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset			0
Derivative Asset, Fair Value, Gross Liability			0
Derivative Asset, Fair Value, Amount Offset Against Collateral			0
Derivative Liability, Fair Value, Gross Liability			104
Derivative Liability, Fair Value, Gross Asset			0
Derivative Liability, Fair Value, Amount Offset Against Collateral			$ 104

[1] Current asset derivative amounts offset include $45 thousand of collateral payable for the period ending December 31, 2018.