Loans and reserve for credit losses (Financing Receivable Credit Quality Indicators) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Commercial real estate:
Owner occupied	$ 264,163		$ 204,998
Non-owner occupied	487,144		347,014
Total commercial real estate loans	751,307		552,012
Construction	115,120		52,503
Residential real estate	190,223		101,557
Commercial and industrial	372,514		254,170
Consumer	37,546		35,990
Total loans	1,466,710		996,232
Acceptable
Commercial real estate:
Owner occupied	220,203		147,865
Non-owner occupied	413,795		278,854
Total commercial real estate loans	633,998		426,719
Construction	106,134		46,274
Residential real estate	184,775		98,633
Commercial and industrial	344,896		242,053
Consumer	37,431		35,984
Total loans	1,307,234		849,663
Pass-Watch
Commercial real estate:
Owner occupied	9,835		19,798
Non-owner occupied	30,187		33,827
Total commercial real estate loans	40,022		53,625
Construction	5,889		2,772
Residential real estate	1,480		1,570
Commercial and industrial	9,929		3,518
Consumer	0		0
Total loans	57,320		61,485
Special Mention
Commercial real estate:
Owner occupied	11,538		14,730
Non-owner occupied	26,631		24,188
Total commercial real estate loans	38,169		38,918
Construction	2,254		2,131
Residential real estate	22		147
Commercial and industrial	13,227		2,694
Consumer	0		0
Total loans	53,672		43,890
Substandard
Commercial real estate:
Owner occupied	22,587		22,605
Non-owner occupied	16,531		10,145
Total commercial real estate loans	39,118		32,750
Construction	843		1,326
Residential real estate	3,946		1,207
Commercial and industrial	4,462		5,905
Consumer	115		6
Total loans	48,484		41,194
Originated Loans
Commercial real estate:
Owner occupied	202,015	[1]	204,998	[1]
Non-owner occupied	362,102	[1]	347,014	[1]
Total commercial real estate loans	564,117	[1]	552,012	[1]
Construction	82,825	[1]	52,503	[1]
Residential real estate	102,004	[1]	101,557	[1]
Commercial and industrial	342,994	[1]	254,170	[1]
Consumer	34,661	[1]	35,990	[1]
Total loans	1,126,601	[1]	996,232	[1]
Originated Loans | Acceptable
Commercial real estate:
Owner occupied	165,642	[1]
Non-owner occupied	328,866	[1]
Total commercial real estate loans	494,508	[1]
Construction	76,716	[1]
Residential real estate	99,687	[1]
Commercial and industrial	317,201	[1]
Consumer	34,616	[1]
Total loans	1,022,728	[1]
Originated Loans | Pass-Watch
Commercial real estate:
Owner occupied	8,700	[1]
Non-owner occupied	11,662	[1]
Total commercial real estate loans	20,362	[1]
Construction	3,467	[1]
Residential real estate	1,480	[1]
Commercial and industrial	9,929	[1]
Consumer	0	[1]
Total loans	35,238	[1]
Originated Loans | Special Mention
Commercial real estate:
Owner occupied	6,093	[1]
Non-owner occupied	15,004	[1]
Total commercial real estate loans	21,097	[1]
Construction	2,254	[1]
Residential real estate	22	[1]
Commercial and industrial	12,032	[1]
Consumer	0	[1]
Total loans	35,405	[1]
Originated Loans | Substandard
Commercial real estate:
Owner occupied	21,580	[1]
Non-owner occupied	6,570	[1]
Total commercial real estate loans	28,150	[1]
Construction	388	[1]
Residential real estate	815	[1]
Commercial and industrial	3,832	[1]
Consumer	45	[1]
Total loans	33,230	[1]
Acquired Loans
Commercial real estate:
Owner occupied	49,284	[2]
Non-owner occupied	106,344	[2]
Total commercial real estate loans	155,628	[2]
Construction	29,775	[2]
Residential real estate	76,453	[2]
Commercial and industrial	25,775	[2]
Consumer	2,416	[2]
Total loans	290,047	[2],[3]
Acquired Loans | Acceptable
Commercial real estate:
Owner occupied	43,483	[2]
Non-owner occupied	79,193	[2]
Total commercial real estate loans	122,676	[2]
Construction	29,369	[2]
Residential real estate	75,082	[2]
Commercial and industrial	24,499	[2]
Consumer	2,346	[2]
Total loans	253,972	[2]
Acquired Loans | Pass-Watch
Commercial real estate:
Owner occupied	1,135	[2]
Non-owner occupied	10,945	[2]
Total commercial real estate loans	12,080	[2]
Construction	0	[2]
Residential real estate	0	[2]
Commercial and industrial	0	[2]
Consumer	0	[2]
Total loans	12,080	[2]
Acquired Loans | Special Mention
Commercial real estate:
Owner occupied	4,386	[2]
Non-owner occupied	11,067	[2]
Total commercial real estate loans	15,453	[2]
Construction	0	[2]
Residential real estate	0	[2]
Commercial and industrial	1,195	[2]
Consumer	0	[2]
Total loans	16,648	[2]
Acquired Loans | Substandard
Commercial real estate:
Owner occupied	280	[2]
Non-owner occupied	5,139	[2]
Total commercial real estate loans	5,419	[2]
Construction	406	[2]
Residential real estate	1,371	[2]
Commercial and industrial	81	[2]
Consumer	70	[2]
Total loans	7,347	[2]
Acquired Covered Loans
Commercial real estate:
Owner occupied	12,864	[4]
Non-owner occupied	18,698	[4]
Total commercial real estate loans	31,562	[4]
Construction	2,520	[4]
Residential real estate	11,766	[4]
Commercial and industrial	3,745	[4]
Consumer	469	[4]
Total loans	50,062	[4],[5]
Loans and Leases Receivable, Net Reported Amount, Covered	50,062	[4]
Acquired Covered Loans | Acceptable
Commercial real estate:
Owner occupied	11,078	[4]
Non-owner occupied	5,736	[4]
Total commercial real estate loans	16,814	[4]
Construction	49	[4]
Residential real estate	10,006	[4]
Commercial and industrial	3,196	[4]
Consumer	469	[4]
Total loans	30,534	[4]
Acquired Covered Loans | Pass-Watch
Commercial real estate:
Owner occupied	0	[4]
Non-owner occupied	7,580	[4]
Total commercial real estate loans	7,580	[4]
Construction	2,422	[4]
Residential real estate	0	[4]
Commercial and industrial	0	[4]
Consumer	0	[4]
Total loans	10,002	[4]
Acquired Covered Loans | Special Mention
Commercial real estate:
Owner occupied	1,059	[4]
Non-owner occupied	560	[4]
Total commercial real estate loans	1,619	[4]
Construction	0	[4]
Residential real estate	0	[4]
Commercial and industrial	0	[4]
Consumer	0	[4]
Total loans	1,619	[4]
Acquired Covered Loans | Substandard
Commercial real estate:
Owner occupied	727	[4]
Non-owner occupied	4,822	[4]
Total commercial real estate loans	5,549	[4]
Construction	49	[4]
Residential real estate	1,760	[4]
Commercial and industrial	549	[4]
Consumer	0	[4]
Loans and Leases Receivable, Net Reported Amount, Covered	$ 7,907	[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

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

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

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