Investments, Securities with Continuous Unrealized Loss Position (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) Securities	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) Securities
Available-for-sale securities, continuous unrealized loss position, Fair Value [Abstract]
Less than 12 months	$ 85,665		$ 29,783
12 months or longer	0		6,037
Total	85,665		35,820
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	8,139		220
12 months or longer	0		127
Total	8,139		$ 347
Gross OTTI losses charged to realized gains	$ 0	$ 0
Number of securities in unrealized loss position | Securities	69		30
U.S. Treasury Securities and Obligations of U.S. Government Agencies and Authorities [Member]
Available-for-sale securities, continuous unrealized loss position, Fair Value [Abstract]
Less than 12 months	$ 1,858		$ 3,432
12 months or longer	0		3,533
Total	1,858		6,965
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	61		22
12 months or longer	0		31
Total	61		53
Obligations of States and Political Subdivisions [Member]
Available-for-sale securities, continuous unrealized loss position, Fair Value [Abstract]
Less than 12 months	4,153		3,106
12 months or longer	0		0
Total	4,153		3,106
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	10		53
12 months or longer	0		0
Total	10		53
Corporate Securities [Member]
Available-for-sale securities, continuous unrealized loss position, Fair Value [Abstract]
Less than 12 months	79,654		23,245
12 months or longer	0		2,504
Total	79,654		25,749
Available-for-sale Securities, Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months	8,068		145
12 months or longer	0		96
Total	$ 8,068		$ 241