Federal Taxes on Income - Narrative (Details) - USD ($)		12 Months Ended
	Jan. 29, 2015	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2015
Operating Loss Carryforwards [Line Items]
Retained earnings on which federal income taxes have not been provided		$ 6,400,000
Deferred tax asset carryforward, charitable contribution		0	$ (1,515,000)
Deferred tax asset valuation allowance		0	1,224,000
Unrecognized tax assets		0	0
Interest and penalties recognized		0	$ 0
Contributions to charitable organization
Operating Loss Carryforwards [Line Items]
Value of charitable consideration, cash portion	$ 400,000			$ 400,000
Value of charitable consideration, stock potion, value		$ 5,900,000		9,300,000
Value of charitable contribution				9,700,000
Deferred tax asset carryforward, charitable contribution				(3,300,000)
Valuation allowance, charitable contribution				$ 1,900,000