Business Combinations (Changes in Goodwill) (Details) - Ozark National Life Insurance Company - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Jan. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Gross goodwill as of beginning of year	$ 13,864	$ 0
Goodwill resulting from business acquisition	0	13,864
Gross goodwill, before impairments	13,864	13,864
Accumulated impairment as of beginning of year		0		$ 0
Current year impairments	0	0
Net goodwill as of end of period	$ 13,864	$ 13,864	$ 13,864