Parent Company Financial Information - OCI (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Parent Company Financial Information
Net income	$ 3,478	$ 4,002	$ 3,800	$ 4,069	$ 4,352	$ 3,429	$ 2,949	$ (1,765)	$ 15,349	$ 8,965	$ 10,841
Other comprehensive income:
Unrealized security holding (losses) / gains									(164)	8,075	(8,565)
Reclassification for net gains on investments included in net income									(641)	(646)	(3,926)
Other comprehensive (loss) / income, before income tax (benefit) / expense									(805)	7,429	(12,491)
Income tax (benefit) / expense related to items of other comprehensive income									(339)	3,072	(5,141)
Other comprehensive (loss) / income									(466)	4,357	(7,350)
Comprehensive income									14,883	13,322	3,491
Heritage Oaks Bancorp
Parent Company Financial Information
Net income									$ 15,349	$ 8,965	$ 10,841