Long-Term Debt and Short-Term Borrowings, Interest Rate Swap Agreement (Details) - Interest Rate Swap [Member] - Variable Rate Pennsylvania Economic Development Financing Authority Exempt Facilities Revenue Refunding Bonds Series 2008A, due 2029 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest Rate Swap Agreement [Abstract]
Notional amount of swap	$ 12,000
Potential payment to counterparty	$ 2,307
Fixed interest rate	3.16%
Net payment rate on swap	1.84%	1.97%
Interest rate spread	0.75%	0.31%
Overall effective rate, including variable interest and swap payments	3.91%	3.47%
LIBOR [Member]
Interest Rate Swap Agreement [Abstract]
Percentage of variable interest rate	59.00%
Term of variable rate	1 month