Loans (Credit Quality Indicators - Residential, Consumer) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Current loans	$ 3,877,310	$ 3,666,738
Past due loans	15,689	13,622
Residential Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Current loans	1,437,661	1,349,867
Past due loans	11,429	10,520
Home Equity [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Current loans	288,178	278,637
Past due loans	2,696	1,989
Other Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Current loans	20,044	26,202
Past due loans	130	33
Total Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Current loans	308,222	304,839
Past due loans	$ 2,826	$ 2,022