Loans and reserve for credit losses (Schedule of Accounts, Notes, Loans and Financing Receivable) (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Commercial real estate:
Owner occupied		$ 314,992	$ 259,109
Non-owner occupied		520,001	497,543
Total commercial real estate loans		834,993	756,652
Construction		134,607	125,428
Residential real estate		272,315	204,687
Commercial and industrial		366,110	368,475
Consumer		39,444	37,298
Total loans		1,647,469	1,492,540
Less:
Deferred loan fees		(1,608)	(1,703)
Reserve for loan losses		(26,623)	(22,053)
Loans, net, Amount		$ 1,619,238	$ 1,468,784
Owner occupied, Percent		19.10%	17.40%
Non-owner occupied, Percent		31.60%	33.30%
Total commercial real estate loans, Percent		50.70%	50.70%
Construction, Percent		8.20%	8.40%
Residential real estate, Percent		16.50%	13.70%
Commercial and industrial, Percent		22.20%	24.70%
Consumer, Percent		2.40%	2.50%
Total loans, Percent		100.00%	100.00%
Originated Loans
Commercial real estate:
Owner occupied	[1],[2]	$ 263,621	$ 198,845
Non-owner occupied	[1],[2]	421,749	383,287
Total commercial real estate loans	[1],[2]	685,370	582,132
Construction	[1],[2]	121,737	100,437
Residential real estate	[1],[2]	206,521	122,478
Commercial and industrial	[1],[2]	344,410	342,746
Consumer	[1],[2]	37,786	34,897
Total loans	[1],[2],[3]	1,395,824	1,182,690
Less:
Deferred loan fees	[2]	(1,608)	(1,703)
Reserve for loan losses	[2]	(26,623)	(22,053)
Loans, net, Amount	[2]	$ 1,367,593	$ 1,158,934
Owner occupied, Percent	[2]	18.90%	16.80%
Non-owner occupied, Percent	[2]	30.20%	32.40%
Total commercial real estate loans, Percent	[2]	49.10%	49.20%
Construction, Percent	[2]	8.70%	8.50%
Residential real estate, Percent	[2]	14.80%	10.40%
Commercial and industrial, Percent	[2]	24.70%	29.00%
Consumer, Percent	[2]	2.70%	2.90%
Total loans, Percent	[2]	100.00%	100.00%
Acquired Loans
Commercial real estate:
Owner occupied	[4],[5]	$ 40,761	$ 48,413
Non-owner occupied	[4],[5]	88,046	102,890
Total commercial real estate loans	[4],[5]	128,807	151,303
Construction	[4],[5]	10,749	22,564
Residential real estate	[4],[5]	58,246	71,385
Commercial and industrial	[4],[5]	19,277	22,444
Consumer	[4],[5]	1,365	1,963
Total loans	[4],[5],[6]	$ 218,444	$ 269,659
Less:
Owner occupied, Percent	[4]	18.70%	18.00%
Non-owner occupied, Percent	[4]	40.30%	38.20%
Total commercial real estate loans, Percent	[4]	59.00%	56.20%
Construction, Percent	[4]	4.90%	8.40%
Residential real estate, Percent	[4]	26.70%	26.50%
Commercial and industrial, Percent	[4]	8.80%	8.30%
Consumer, Percent	[4]	0.60%	0.60%
Total loans, Percent	[4]	100.00%	100.00%
Acquired Covered Loans
Commercial real estate:
Owner occupied	[7],[8]	$ 10,610	$ 11,851
Non-owner occupied	[7],[8]	10,206	11,366
Total commercial real estate loans	[7],[8]	20,816	23,217
Construction	[7],[8]	2,121	2,427
Residential real estate	[7],[8]	7,548	10,824
Commercial and industrial	[7],[8]	2,423	3,285
Consumer	[7],[8]	293	438
Total loans	[7],[8],[9]	$ 33,201	$ 40,191
Less:
Owner occupied, Percent	[7]	32.00%	29.50%
Non-owner occupied, Percent	[7]	30.70%	28.30%
Total commercial real estate loans, Percent	[7]	62.70%	57.80%
Construction, Percent	[7]	6.40%	6.00%
Residential real estate, Percent	[7]	22.70%	26.90%
Commercial and industrial, Percent	[7]	7.30%	8.20%
Consumer, Percent	[7]	0.90%	1.10%
Total loans, Percent	[7]	100.00%	100.00%

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

[2] Originated loans are loans organically made through the Company's normal and customary origination process, including ARM purchases

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

[4] Acquired loans are loans acquired in the acquisition of Home Federal Bancorp, Inc. ("Home"), discussed elsewhere in this Quarterly Report on Form 10-Q (the "Form 10-Q"), less acquired covered loans.

[5] Acquired loans are loans acquired in the acquisition of Home less acquired covered loans.

[6] Acquired loans are loans acquired in the acquisition of Home less acquired covered loans.

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

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

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