Loans and Allowance for Loan Losses, Rollforward of Purchase Credit Impaired Loans (Details) - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016
Business Combination, Acquired Receivables [Abstract]
Gross Contractual Receivable	$ 19,960	$ 16,274
Acquisitions		1,359
Settlements	(3,803)	(6,017)
Additional fundings	117	852
Gross Contractual Receivable	16,274	12,468
Accretable Yield	0	0
Acquired Accretable Yield		0
Settlements	0	0
Additional fundings	0	0
Accretable Yield	0	0
Nonaccretable Yield	(5,703)	(4,143)
Acquired Nonaccretable Yield		(812)
Settlements	1,560	1,322
Additional fundings	0	0
Nonaccretable Yield	(4,143)	(3,633)
Carrying Value	14,257	12,131
Acquisitions,		547
Settlements	(2,243)	(4,695)
Additional fundings	117	852
Carrying Value	$ 12,131	$ 8,835