Parent Company Financial Information - OCI (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Parent Company Financial Information
Net income	$ 4,550	$ 4,183	$ 4,215	$ 3,985	$ 3,478	$ 4,002	$ 3,800	$ 4,069	$ 16,933	$ 15,349	$ 8,965
Other comprehensive income, net of tax:
Unrealized holding (losses) gains on securities arising during the period									(3,509)	(164)	8,075
Reclassification for net gains on investments included in net income									(891)	(641)	(646)
Other comprehensive (loss) income, before income tax (benefit) expense									(4,400)	(805)	7,429
Income tax (benefit) expense related to items of other comprehensive income									(1,850)	(339)	3,072
Other comprehensive (loss) income									(2,550)	(466)	4,357
Comprehensive income									14,383	14,883	13,322
Heritage Oaks Bancorp
Parent Company Financial Information
Net income									$ 16,933	$ 15,349	$ 8,965