Fair Value Measurements, Level 3 Valuations (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Reconciliation of level 3 fair value category measured at fair value on a recurring basis [Roll Forward]
Balance at Beginning of Period	$ 4,839
Purchases / Additions	479
Sales / Reductions	675
Net Realized Gains (Losses)	0
Net Unrealized Gains (Losses)	0
Balance at End of Period	4,643
Available-for-Sale Debt Securities [Member]
Reconciliation of level 3 fair value category measured at fair value on a recurring basis [Roll Forward]
Balance at Beginning of Period	1,593
Purchases / Additions	479
Sales / Reductions	675
Net Realized Gains (Losses)	0
Net Unrealized Gains (Losses)	0
Balance at End of Period	1,397
Equity Securities [Member]
Reconciliation of level 3 fair value category measured at fair value on a recurring basis [Roll Forward]
Balance at Beginning of Period	3,246
Purchases / Additions	0
Sales / Reductions	0
Net Realized Gains (Losses)	0
Net Unrealized Gains (Losses)	0
Balance at End of Period	$ 3,246