Loans (Risk Ratings) (Details) - USD ($)		Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans		$ 3,123,301,000	$ 3,187,730,000
Deposit liabilities reclassified as loans receivable		202,000	519,000
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			3,162,138,000
Watch [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			721,000
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			22,622,000
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			2,249,000
Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		15,540,000
2019		17,545,000
2018		12,124,000
2017		14,783,000
2016		8,182,000
Prior		30,625,000
Revolving Loans		27,274,000
Total Loans		126,073,000	103,879,000
Commercial And Industrial [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		15,540,000
2019		16,774,000
2018		12,124,000
2017		14,783,000
2016		8,182,000
Prior		27,208,000
Revolving Loans		27,274,000
Total Loans		121,885,000	100,095,000
Commercial And Industrial [Member] | Watch [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		2,408,000
Total Loans		2,408,000
Commercial And Industrial [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		750,000
Total Loans		750,000	3,493,000
Commercial And Industrial [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2019		771,000
Prior		259,000
Total Loans		1,030,000	291,000
Residential Mortgages [Member] | Closed-end [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		412,000
2019		30,094,000
2018		357,167,000
2017		404,019,000
2016		292,070,000
Prior		474,639,000
Total Loans		1,558,401,000	1,621,419,000
Residential Mortgages [Member] | Revolving Home Equity [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans		60,296,000
Total Loans		60,296,000	59,231,000
Residential Mortgages [Member] | Pass [Member] | Closed-end [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		412,000
2019		30,094,000
2018		356,704,000
2017		404,019,000
2016		292,070,000
Prior		472,400,000
Total Loans		1,555,699,000	1,619,034,000
Residential Mortgages [Member] | Pass [Member] | Revolving Home Equity [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans		59,491,000
Total Loans		59,491,000	58,816,000
Residential Mortgages [Member] | Watch [Member] | Closed-end [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		304,000
Total Loans		304,000	306,000
Residential Mortgages [Member] | Watch [Member] | Revolving Home Equity [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans		415,000
Total Loans		415,000	415,000
Residential Mortgages [Member] | Special Mention [Member] | Closed-end [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			890,000
Residential Mortgages [Member] | Substandard [Member] | Closed-end [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2018		463,000
Prior		1,935,000
Total Loans		2,398,000	1,189,000
Residential Mortgages [Member] | Substandard [Member] | Revolving Home Equity [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans		390,000
Total Loans		390,000
Commercial Mortgages [Member] | Multifamily Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		10,809,000
2019		155,469,000
2018		166,365,000
2017		165,179,000
2016		37,000,000
Prior		279,037,000
Total Loans		813,859,000	835,013,000
Commercial Mortgages [Member] | Other Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		22,871,000
2019		43,516,000
2018		52,786,000
2017		56,937,000
2016		111,418,000
Prior		154,653,000
Total Loans		442,181,000	447,484,000
Commercial Mortgages [Member] | Owner-occupied Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		3,550,000
2019		44,014,000
2018		9,285,000
2017		12,148,000
2016		12,831,000
Prior		38,389,000
Total Loans		120,217,000	118,792,000
Commercial Mortgages [Member] | Pass [Member] | Multifamily Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		10,809,000
2019		155,469,000
2018		166,365,000
2017		163,857,000
2016		33,366,000
Prior		279,037,000
Total Loans		808,903,000	831,360,000
Commercial Mortgages [Member] | Pass [Member] | Other Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		22,871,000
2019		43,516,000
2018		52,786,000
2017		56,937,000
2016		101,642,000
Prior		153,781,000
Total Loans		431,533,000	437,655,000
Commercial Mortgages [Member] | Pass [Member] | Owner-occupied Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020		3,550,000
2019		44,014,000
2018		9,285,000
2017		10,267,000
2016		12,831,000
Prior		35,163,000
Total Loans		115,110,000	113,534,000
Commercial Mortgages [Member] | Watch [Member] | Multifamily Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2017		1,322,000
Total Loans		1,322,000
Commercial Mortgages [Member] | Watch [Member] | Other Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2016		9,776,000
Total Loans		9,776,000
Commercial Mortgages [Member] | Watch [Member] | Owner-occupied Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		2,515,000
Total Loans		2,515,000
Commercial Mortgages [Member] | Special Mention [Member] | Multifamily Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2016		2,309,000
Total Loans		2,309,000	3,653,000
Commercial Mortgages [Member] | Special Mention [Member] | Other Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			9,829,000
Commercial Mortgages [Member] | Special Mention [Member] | Owner-occupied Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans			4,757,000
Commercial Mortgages [Member] | Substandard [Member] | Multifamily Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2016		1,325,000
Total Loans		1,325,000
Commercial Mortgages [Member] | Substandard [Member] | Other Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		872,000
Total Loans		872,000
Commercial Mortgages [Member] | Substandard [Member] | Owner-occupied Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2017		1,881,000
Prior		711,000
Total Loans		2,592,000	501,000
Consumer And Other Excluding Overdrafts [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	[1]	253,000
2019	[1]	485,000
2018	[1]	85,000
2017	[1]	40,000
2016	[1]	801,000
Prior	[1]	408,000
Total Loans	[1]	2,072,000
Consumer And Other Excluding Overdrafts [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	[1]	253,000
2019	[1]	226,000
2018	[1]	85,000
2017	[1]	40,000
2016	[1]	801,000
Prior	[1]	408,000
Total Loans	[1]	1,813,000	1,644,000
Consumer And Other Excluding Overdrafts [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2019	[1]	259,000
Total Loans	[1]	$ 259,000	268,000
Consumer And Other Excluding Overdrafts [Member] | Internal Investment Grade [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	[1]		$ 1,912,000

[1] Deposit account overdrafts were $202,000 and $519,000 at March 31, 2020 and December 31, 2019, respectively. Overdrafts are not assigned a risk rating and are therefore excluded from consumer loans in the tables above.