Related Party Transactions (Debt Agreements) (Details) - Affiliated Entity - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 672,833	$ 661,512
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 37,468	37,468
Interest Rate	3.64%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 103,039	103,039
Interest Rate	3.64%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 93,671	93,671
Interest Rate	3.64%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 93,671	93,671
Interest Rate	3.47%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 93,671	93,671
Interest Rate	4.39%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 28,102	28,102
Interest Rate	4.39%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 93,671	93,671
Interest Rate	3.95%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 37,468	37,468
Interest Rate	3.95%
Prudential Insurance Loan Issued 4/20/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 46,835	46,835
Interest Rate	3.95%
Prudential Insurance Loan Issued 6/28/2016
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 26,000	26,000
Interest Rate	2.59%
Prudential Funding Loan Issued 12/16/2019
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 0	1,298
Interest Rate	2.02%
Prudential Funding Loan Issued 12/17/2019
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 0	1,478
Interest Rate	2.02%
Prudential Funding Loan Issued 12/17/2019
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 0	502
Interest Rate	2.02%
Prudential Funding Loan Issued 12/18/2019
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 0	4,638
Interest Rate	2.02%
Prudential Funding Loan Issued 9/25/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 387	0
Interest Rate	0.26%
Prudential Funding Loan Issued 9/25/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 2,962	0
Interest Rate	0.26%
Prudential Funding Loan Issued 9/28/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 4,014	0
Interest Rate	0.26%
Prudential Funding Loan Issued 9/28/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 325	0
Interest Rate	0.26%
Prudential Funding Loan Issued 9/29/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 194	0
Interest Rate	0.26%
Prudential Funding Loan Issued 9/30/2020
Related Party Transaction [Line Items]
Short-term and Long-term debt	$ 11,355	$ 0
Interest Rate	0.26%