Revenue from Contracts with Customers Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 51,818	$ 50,230	$ 157,449	$ 150,732
Noninterest Income	69,931	72,284	214,396	209,405
Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	41,410	40,601	127,552	121,911
Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,496	8,412	24,456	24,738
Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,912	1,217	5,441	4,083
Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	18,113	22,054	56,947	58,673
Operating Segments [Member] | Commercial Banking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,637	5,788	16,784	17,316
Noninterest Income	13,987	18,305	42,643	48,662
Operating Segments [Member] | Commercial Banking [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,987	3,211	9,108	9,613
Operating Segments [Member] | Commercial Banking [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	2,650	2,577	7,676	7,703
Operating Segments [Member] | Commercial Banking [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Operating Segments [Member] | Commercial Banking [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	8,350	12,517	25,859	31,346
Operating Segments [Member] | Community Banking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,552	22,302	66,362	65,624
Noninterest Income	28,115	26,848	81,172	78,421
Operating Segments [Member] | Community Banking [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	16,047	16,107	47,701	47,079
Operating Segments [Member] | Community Banking [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,855	5,843	16,806	17,060
Operating Segments [Member] | Community Banking [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	650	352	1,855	1,485
Operating Segments [Member] | Community Banking [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	5,563	4,546	14,810	12,797
Operating Segments [Member] | HSA Bank [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	23,526	22,159	74,082	67,710
Noninterest Income	23,526	22,159	74,082	67,710
Operating Segments [Member] | HSA Bank [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,264	21,294	70,496	65,112
Operating Segments [Member] | HSA Bank [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Operating Segments [Member] | HSA Bank [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,262	865	3,586	2,598
Operating Segments [Member] | HSA Bank [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	0	0	0	0
Corporate, Non-Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	103	(19)	221	82
Noninterest Income	4,303	4,972	16,499	14,612
Corporate, Non-Segment [Member] | Deposit service fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	112	(11)	247	107
Corporate, Non-Segment [Member] | Wealth and investment services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(9)	(8)	(26)	(25)
Corporate, Non-Segment [Member] | Other non interest income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Corporate, Non-Segment [Member] | Non-interest income within the scope of other GAAP topics [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 4,200	$ 4,991	$ 16,278	$ 14,530