Loans and reserve for credit losses (Past Due Financing Receivables) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	$ 6,672		$ 2,260
90 days or more past due	4,931		5,270
Total past due	11,603		7,530
Current	1,455,107		988,702
Total loans	1,466,710		996,232
Commercial Real Estate Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	1,255		959
90 days or more past due	3,053		2,905
Total past due	4,308		3,864
Current	259,855		201,134
Total loans	264,163		204,998
Commercial Real Estate Non Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	934		0
90 days or more past due	359		0
Total past due	1,293		0
Current	485,851		347,014
Total loans	487,144		347,014
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	2,189		959
90 days or more past due	3,412		2,905
Total past due	5,601		3,864
Current	745,706		548,148
Total loans	751,307		552,012
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	419		215
90 days or more past due	206		119
Total past due	625		334
Current	114,495		52,169
Total loans	115,120		52,503
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	3,431		436
90 days or more past due	752		163
Total past due	4,183		599
Current	186,040		100,958
Total loans	190,223		101,557
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	425		597
90 days or more past due	516		2,077
Total past due	941		2,674
Current	371,573		251,496
Total loans	372,514		254,170
Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	208		53
90 days or more past due	45		6
Total past due	253		59
Current	37,293		35,931
Total loans	37,546		35,990
Originated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	4,385	[1]
90 days or more past due	3,858	[1]
Total past due	8,243	[1]
Current	1,118,358	[1]
Total loans	1,126,601	[1]	996,232	[1]
Originated Loans | Commercial Real Estate Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	1,255	[1]
90 days or more past due	2,969	[1]
Total past due	4,224	[1]
Current	197,791	[1]
Total loans	202,015	[1]
Originated Loans | Commercial Real Estate Non Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	860	[1]
90 days or more past due	332	[1]
Total past due	1,192	[1]
Current	360,910	[1]
Total loans	362,102	[1]
Originated Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	2,115	[1]
90 days or more past due	3,301	[1]
Total past due	5,416	[1]
Current	558,701	[1]
Total loans	564,117	[1]
Originated Loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	419	[1]
90 days or more past due	39	[1]
Total past due	458	[1]
Current	82,367	[1]
Total loans	82,825	[1]
Originated Loans | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	1,270	[1]
90 days or more past due	0	[1]
Total past due	1,270	[1]
Current	100,734	[1]
Total loans	102,004	[1]
Originated Loans | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	419	[1]
90 days or more past due	473	[1]
Total past due	892	[1]
Current	342,102	[1]
Total loans	342,994	[1]
Originated Loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	162	[1]
90 days or more past due	45	[1]
Total past due	207	[1]
Current	34,454	[1]
Total loans	34,661	[1]
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	1,820	[2]
90 days or more past due	919	[2]
Total past due	2,739	[2]
Current	287,308	[2]
Total loans	290,047	[2],[3]
Acquired Loans | Commercial Real Estate Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[2]
90 days or more past due	0	[2]
Total past due	0	[2]
Current	49,284	[2]
Total loans	49,284	[2]
Acquired Loans | Commercial Real Estate Non Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[2]
90 days or more past due	0	[2]
Total past due	0	[2]
Current	106,344	[2]
Total loans	106,344	[2]
Acquired Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[2]
90 days or more past due	0	[2]
Total past due	0	[2]
Current	155,628	[2]
Total loans	155,628	[2]
Acquired Loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[2]
90 days or more past due	167	[2]
Total past due	167	[2]
Current	29,608	[2]
Total loans	29,775	[2]
Acquired Loans | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	1,774	[2]
90 days or more past due	752	[2]
Total past due	2,526	[2]
Current	73,927	[2]
Total loans	76,453	[2]
Acquired Loans | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[2]
90 days or more past due	0	[2]
Total past due	0	[2]
Current	25,775	[2]
Total loans	25,775	[2]
Acquired Loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	46	[2]
90 days or more past due	0	[2]
Total past due	46	[2]
Current	2,370	[2]
Total loans	2,416	[2]
Acquired Covered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	467	[4]
90 days or more past due	154	[4]
Total past due	621	[4]
Current	49,441	[4]
Total loans	50,062	[4],[5]
Acquired Covered Loans | Commercial Real Estate Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[4]
90 days or more past due	84	[4]
Total past due	84	[4]
Current	12,780	[4]
Total loans	12,864	[4]
Acquired Covered Loans | Commercial Real Estate Non Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	74	[4]
90 days or more past due	27	[4]
Total past due	101	[4]
Current	18,597	[4]
Total loans	18,698	[4]
Acquired Covered Loans | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	74	[4]
90 days or more past due	111	[4]
Total past due	185	[4]
Current	31,377	[4]
Total loans	31,562	[4]
Acquired Covered Loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[4]
90 days or more past due	0	[4]
Total past due	0	[4]
Current	2,520	[4]
Total loans	2,520	[4]
Acquired Covered Loans | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	387	[4]
90 days or more past due	0	[4]
Total past due	387	[4]
Current	11,379	[4]
Total loans	11,766	[4]
Acquired Covered Loans | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	6	[4]
90 days or more past due	43	[4]
Total past due	49	[4]
Current	3,696	[4]
Total loans	3,745	[4]
Acquired Covered Loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 days past due	0	[4]
90 days or more past due	0	[4]
Total past due	0	[4]
Current	469	[4]
Total loans	$ 469	[4]

[1] Originated loans are loans organically made through the Company's normal and customary origination process

[2] Acquired loans are loans acquired in the acquisition of Home, discussed elsewhere in this report, less acquired covered loans

[3] Acquired loans are loans acquired in the acquisition of Home, discussed elsewhere in this report

[4] Acquired covered loans acquired in the acquisition of Home that are covered under FDIC loss share agreements

[5] Acquired covered loans are loans in the Home portfolio that are covered under FDIC loss share agreements