Loans and Allowance for Loan Losses (Changes in Carrying Amount of Purchased Credit Impaired Loans and Related Accretable Yield) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Carrying Amount of Loans, Balance at beginning of period	$ 129,596	$ 153,403
Carrying Amount of Loans, Additions	118,047
Carrying Amount of Loans, Payments received, net	(28,846)	(39,556)
Carrying Amount of Loans, Accretion	9,823	15,749
Carrying Amount of Loans, Balance at end of period	228,620	129,596
Accretable Yield, Balance at beginning of period	37,294	62,517
Accretable Yield, Additions	6,238
Accretable Yield, Payments received, net	(3,517)	(5,779)
Accretable Yield, Accretion	(9,823)	(15,749)
Accretable Yield, Increase (decrease) in expected cash flows based on actual cash flow and changes in cash flow assumptions	4,190	(3,695)
Accretable Yield, Balance at end of period	$ 34,382	$ 37,294