Fair Value Qualitative information about Level 3 fair value measurements (Details) $ in Thousands	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	$ 5,632,280	$ 5,580,780
Impaired Loan Fair Value	5,462	6,399
Other Assets, Fair Value Disclosure	5,622,367	5,570,136
Loans Held-for-sale, Fair Value Disclosure	4,276	4,158
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	5,627,829	5,576,535
Impaired Loan Fair Value	5,462	6,399
Other Assets, Fair Value Disclosure	5,622,367	5,570,136
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	5,462	6,399
Other Assets, Fair Value Disclosure	3,823	3,674
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	5,462	6,399
Other Assets, Fair Value Disclosure	3,823	3,674
Fair Value, Measurements, Nonrecurring [Member] | Construction Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	728	729
Fair Value, Measurements, Nonrecurring [Member] | Construction Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	728	729
Fair Value, Measurements, Nonrecurring [Member] | Construction Real Estate [Member] | Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	728	729
Fair Value, Measurements, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	3,691	4,059
Fair Value, Measurements, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	3,691	4,059
Fair Value, Measurements, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loan Fair Value		4,059
Fair Value, Measurements, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	2,475	2,295
Fair Value, Measurements, Nonrecurring [Member] | Construction Real Estate - Remaining Commercial [Member] | Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loan Fair Value		1,635
Fair Value, Measurements, Nonrecurring [Member] | Residential Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	620	650
Fair Value, Measurements, Nonrecurring [Member] | Residential Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	620	650
Fair Value, Measurements, Nonrecurring [Member] | Residential Real Estate [Member] | Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loan Fair Value		705
Fair Value, Measurements, Nonrecurring [Member] | Residential Real Estate [Member] | Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Assets, Fair Value Disclosure	620	650
Fair Value [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loan Fair Value		$ 6,399
Fair Value [Member] | Fair Value, Measurements, Nonrecurring [Member] | Commercial Real Estate Portfolio Segment [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	3,691
Fair Value [Member] | Fair Value, Measurements, Nonrecurring [Member] | Residential Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans Receivable, Fair Value Disclosure	$ 136
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.017	0.050
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.607	0.900
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.346	0.261
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.000	0.000
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.450	0.450
Measurement Input, Comparability Adjustment [Member] | Construction Real Estate [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.218	0.217
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.000	0.000
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	1.075	1.075
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.341	0.311
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.009	0.009
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.684	0.684
Measurement Input, Comparability Adjustment [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.284	0.347
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.010	0.000
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.264	0.400
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.103	0.132
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.304	0.304
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.546	0.546
Measurement Input, Comparability Adjustment [Member] | Residential Real Estate [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Market Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.425	0.425
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.108	0.095
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.108	0.108
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.108	0.106
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Minimum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.100	0.130
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Maximum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.130	0.130
Measurement Input, Cap Rate [Member] | Commercial Real Estate Portfolio Segment [Member] | Real Estate [Member] | Weighted Average [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Real Estate Owned, Measurement Input	0.127	0.130
Measurement Input, Cap Rate [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input		0.105
Measurement Input, Cap Rate [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input		0.105
Measurement Input, Cap Rate [Member] | Residential Real Estate [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Income Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input		0.105
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Minimum [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.042	0.042
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Maximum [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.901	0.901
Measurement input replacement cost [Member] | Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Weighted Average [Member] | Valuation, Cost Approach [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans Receivable, Measurement Input	0.107	0.110