Investment Securities (Narrative) (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) item security	Sep. 30, 2018 USD ($) security	Dec. 31, 2018 USD ($) item
Investment Securities [Abstract]
Number of holdings greater than 10 percent of stockholders equity | item		0		0
Income tax expense (benefit) related to net realized gains (losses)	$ 1,495,000		$ 1,495,000
Held-to-maturity securities, Number of sales | security		0	0
Restricted investment securities		$ 412,681,000		$ 342,712,000