Credit Quality and Nonperforming Assets - Carrying Amount and Unpaid Principal Balance of Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance, Total	[1]	$ 15,986	$ 17,050
Impaired Financing Receivable, Carrying Value, Total	[2]	15,242	16,072
Purchased Credit Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance, Total		100	103
Purchased Credit Impaired Loans [Member] | Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance, Total		$ 100	$ 103

[1] Contractual principal balance due from customer.

[2] Principal balance on Company's books, less any direct charge offs.