Age Analysis of Past Due Financing receivables (Details) $ in Thousands	Dec. 31, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($)
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	301	377
Number of Loans 60-89 Days | loan	72	48
Number of Loans 90 Days or More | loan	91	87
Number of Loans Total Past Due | loan	464	512
Principal Balance Total Past Due	$ 19,911	$ 31,057
Current	5,979,694	5,516,664
Total loans	5,999,605	5,547,721	$ 4,970,733	[1]
Recorded Investment >90 Days and Accruing	$ 2	$ 0
Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	8	9
Number of Loans 60-89 Days | loan	32	4
Number of Loans 90 Days or More | loan	6	8
Number of Loans Total Past Due | loan	46	21
Principal Balance Total Past Due	$ 2,833	$ 4,459
Current	899,220	838,817
Total loans	902,053	843,276	860,839
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	5	19
Number of Loans 60-89 Days | loan	8	6
Number of Loans 90 Days or More | loan	8	13
Number of Loans Total Past Due | loan	21	38
Principal Balance Total Past Due	$ 6,580	$ 13,434
Current	3,004,218	2,640,000
Total loans	3,010,798	2,653,434	2,347,323
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	0	0
Number of Loans 60-89 Days | loan	0	0
Number of Loans 90 Days or More | loan	0	1
Number of Loans Total Past Due | loan	0	1
Principal Balance Total Past Due	$ 0	$ 304
Current	320,391	373,064
Total loans	320,391	373,368	265,994
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Small Business [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	9	11
Number of Loans 60-89 Days | loan	0	4
Number of Loans 90 Days or More | loan	19	13
Number of Loans Total Past Due | loan	28	28
Principal Balance Total Past Due	$ 463	$ 171
Current	122,263	96,075
Total loans	122,726	96,246	85,247
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	11	20
Number of Loans 60-89 Days | loan	9	11
Number of Loans 90 Days or More | loan	27	19
Number of Loans Total Past Due | loan	47	50
Principal Balance Total Past Due	$ 6,734	$ 8,601
Current	637,692	630,005
Total loans	644,426	638,606	530,259
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	19	21
Number of Loans 60-89 Days | loan	11	11
Number of Loans 90 Days or More | loan	16	20
Number of Loans Total Past Due | loan	46	52
Principal Balance Total Past Due	$ 3,093	$ 3,767
Current	985,054	924,036
Total loans	988,147	927,803	863,863
Recorded Investment >90 Days and Accruing	$ 0	$ 0
Consumer Portfolio Segment [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan	249	297
Number of Loans 60-89 Days | loan	12	12
Number of Loans 90 Days or More | loan	15	13
Number of Loans Total Past Due | loan	276	322
Principal Balance Total Past Due	$ 208	$ 321
Current	10,856	14,667
Total loans	11,064	14,988	$ 17,208
Recorded Investment >90 Days and Accruing	2	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	4,519	12,717
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	100	399
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,518	7,349
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	323	93
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,277	3,119
Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,117	1,526
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	184	231
Financing Receivables, 60 to 89 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	4,944	5,674
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	253	1,021
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,957	1,627
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	0	9
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,950	2,049
Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	767	903
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	17	65
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	10,448	12,666
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	2,480	3,039
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	3,105	4,458
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	0	304
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	140	69
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	3,507	3,433
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	1,209	1,338
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due	$ 7	$ 25

[1] The amount of net deferred costs on originated loans included in the ending balance was $5.1 million, $4.3 million, and $2.8 million at December 31, 2016, 2015, and 2014, respectively. Net unamortized discounts on acquired loans not deemed to be PCI included in the ending balance was $8.6 million, $6.6 million, and $1.9 million at December 31, 2016, 2015, and 2014, respectively.