Acquisitions and FDIC Indemnification Asset (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered			$ 1,896	$ 4,881
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion		$ 0
Loans and Leases Receivable, Disposals	$ (36)	(2,872)
Total Covered Assets	1,860	2,009
Consumer Loan [Member]
Business Acquisition [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered			0	1,430
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion		0
Loans and Leases Receivable, Disposals	0	(1,430)
Total Covered Assets	0	0
Commercial Loan [Member]
Business Acquisition [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered			$ 1,896	$ 3,451
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion		0
Loans and Leases Receivable, Disposals	(36)	(1,442)
Total Covered Assets	$ 1,860	$ 2,009