Investments (Equity Securities) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Debt and Equity Securities, FV-NI [Line Items]
Equity security	$ 15,827,000		$ 15,827,000		$ 15,068,000
Realized investment gains (losses), net	(2,869,000)	$ (178,000)	3,092,000	$ (753,000)
Stock Mutual Funds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	3,142,000		3,142,000		2,906,000
Bond Mutual Funds [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	12,255,000		12,255,000		11,774,000
Common stock [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	120,000		120,000		94,000
Non-redeemable Preferred Stock [Member]
Debt and Equity Securities, FV-NI [Line Items]
Equity security	310,000		310,000		$ 294,000
Equity Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Realized investment gains (losses), net	$ 155,000	$ (86,000)	$ 757,000	$ (388,000)