Income Taxes (Tables)

6 Months Ended

Jun. 30, 2020

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The following table summarizes the differences between our effective tax rate and the federal statutory rate (in thousands):

	Three Months Ended June 30,
	2020				2019
Income Before Income Taxes	$	20,776			$	25,436
Income tax calculated at federal statutory rate	4,363		21.0	%	5,341		21.0	%
Permanent or flow-through adjustments:
State income tax, net of federal provisions	5		—		237		0.9
Flow-through repairs deductions	(3,208)		(15.4)		(2,153)		(8.5)
Production tax credits	(1,737)		(8.5)		(1,406)		(5.5)
Amortization of excess deferred income tax	(153)		(0.7)		(189)		(0.7)
Plant and depreciation of flow-through items	59		0.3		(663)		(2.6)
Recognition of unrecognized tax benefit	—		—		(23,201)		(91.2)
Other, net	(47)		(0.2)		(192)		(0.8)
	(5,081)		(24.5)		(27,567)		(108.4)
Income tax benefit	$	(718)	(3.5)	%	$	(22,226)	(87.4)	%

	Six Months Ended June 30,
	2020				2019
Income Before Income Taxes	$	69,674			$	99,815
Income tax calculated at federal statutory rate	14,631		21.0	%	20,961		21.0	%
Permanent or flow through adjustments:
State income, net of federal provisions	27		0.1		1,165		1.2
Flow-through repairs deductions	(10,646)		(15.3)		(10,088)		(10.1)
Production tax credits	(5,348)		(7.7)		(5,838)		(5.8)
Share-based compensation	(609)		(0.9)		186		0.2
Amortization of excess deferred income tax	(509)		(0.7)		(1,565)		(1.6)
Plant and depreciation of flow through items	196		0.3		(2,186)		(2.2)
Recognition of unrecognized tax benefit	—		—		(22,825)		(22.9)
Other, net	(266)		(0.4)		(463)		(0.5)
	(17,155)		(24.6)		(41,614)		(41.7)
Income tax benefit	$	(2,524)	(3.6)	%	$	(20,653)	(20.7)	%