Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 13,963,000	$ 13,407,000	$ 29,763,000	$ 26,649,000
Other sources of noninterest income	44,674,000	39,352,000	82,923,000	68,241,000
Total noninterest income	58,637,000	52,759,000	112,686,000	94,890,000
Contract assets	0		0		$ 0
Contract liabilities	0		0		$ 0
Consumer and Business Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,496,000	9,709,000	20,951,000	19,370,000
Other sources of noninterest income	4,447,000	4,794,000	9,394,000	8,905,000
Total noninterest income	13,943,000	14,503,000	30,345,000	28,275,000
Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,426,000	3,688,000	8,765,000	7,253,000
Other sources of noninterest income	29,461,000	29,968,000	57,578,000	50,947,000
Total noninterest income	33,887,000	33,656,000	66,343,000	58,200,000
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,000	10,000	47,000	26,000
Other sources of noninterest income	10,766,000	4,590,000	15,951,000	8,389,000
Total noninterest income	10,807,000	4,600,000	15,998,000	8,415,000
Deposit service charges and related fee income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,111,000	8,706,000	19,460,000	17,229,000
Deposit service charges and related fee income | Consumer and Business Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,166,000	5,397,000	11,710,000	10,630,000
Deposit service charges and related fee income | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,904,000	3,299,000	7,703,000	6,573,000
Deposit service charges and related fee income | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	41,000	10,000	47,000	26,000
Card income
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	761,000	901,000	1,859,000	1,846,000
Card income | Consumer and Business Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	639,000	747,000	1,537,000	1,507,000
Card income | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	122,000	154,000	322,000	339,000
Card income | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Wealth management fees
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,091,000	3,800,000	8,444,000	7,574,000
Wealth management fees | Consumer and Business Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,691,000	3,565,000	7,704,000	7,233,000
Wealth management fees | Commercial Banking
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	400,000	235,000	740,000	341,000
Wealth management fees | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 0	$ 0