Long-Term Debt (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Mar. 09, 2015
Debt Instrument [Line Items]
Notes payable aggregate principal amount	$ 237,890
Other long-term debt maturity year	2053
Subordinated Notes [Member] | Subordinated Notes Payable, Maturing June 2045 [Member]
Debt Instrument [Line Items]
Notes payable issuance date	Mar. 09, 2015
Notes payable aggregate principal amount	$ 150,000	$ 150,000	$ 150,000
Notes payable maturity date	Jun. 15, 2045
Notes payable interest rate	5.95%
Notes payable beginning payment date	Jun. 01, 2015
Notes payable redemption date	Jun. 15, 2020
Other Long-Term Debt [Member]
Debt Instrument [Line Items]
Notes payable aggregate principal amount	$ 87,890	$ 79,598
Notes payable agreement period	7 years