Commitments, Contingencies and Other Items (Details) plaintiff in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) plaintiff
Loss Contingencies [Line Items]
Estimate of possible loss	$ 22,000,000
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Estimate of possible loss	100,000
U.S. District Court for the District of Minnesota
Loss Contingencies [Line Items]
Amount awarded to other party	15,500,000
Litigation settlement, expense	$ 3,500,000
Number of plaintiffs (approximately) | plaintiff	12