Parent Company Financial Information - Cash Flow (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
Cash Flows from Operating Activities
Net income	$ 4,550	$ 4,183	$ 4,215	$ 3,985	$ 3,478	$ 4,002	$ 3,800	$ 4,069	$ 16,933	$ 15,349	$ 8,965
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Share-based compensation expense									1,362	1,092	993
Loss on sale of investment securities									(891)	(641)	(646)
Gain on extinguishment of debt										(552)
(Increase) decrease in other assets and other liabilities, net									(143)	1,838	48
Net cash provided by operating activities									27,624	21,153	20,030
Cash Flows from Investing Activities
Sale of other investments									107,566	55,184	129,074
Proceeds from sale of assets										1,957	3,590
Net cash used in investing activities									(160,511)	(155,015)	(58,001)
Cash Flows from Financing Activities
Repurchases of common stock									(1,635)	(28)	(387)
Decrease in junior subordinated debentures										(2,550)
Dividends paid									(8,217)	(7,851)	(2,742)
Stock issuance costs											(381)
Net cash provided by financing activities									113,838	168,205	47,313
Net (decrease) increase in cash and cash equivalents									(19,049)	34,343	9,342
Cash and cash equivalents, beginning of period				69,923				35,580	69,923	35,580	26,238
Cash and cash equivalents, end of period	50,874				69,923				50,874	69,923	35,580
Heritage Oaks Bancorp
Cash Flows from Operating Activities
Net income									16,933	15,349	8,965
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Share-based compensation expense									257	294	211
Amortization of premium on borrowings									169	199	175
Loss on sale of investment securities									41
Gain on extinguishment of debt										(450)
Undistributed (income) loss of subsidiaries									(7,724)	(5,894)	180
(Increase) decrease in other assets and other liabilities, net									811	30	(868)
Net cash provided by operating activities									10,487	9,528	8,663
Cash Flows from Investing Activities
Sale of other investments									59
Cash acquired in MISN Transaction, net											(3,928)
Proceeds from sale of assets											338
Other											(100)
Net cash used in investing activities									59		(3,690)
Cash Flows from Financing Activities
Proceeds from the exercise of options									747	293	453
Repurchases of common stock									(1,635)	(28)	(387)
Decrease in junior subordinated debentures										(2,550)
Dividends paid									(8,217)	(7,851)	(2,742)
Stock issuance costs											(381)
Net cash provided by financing activities									(9,105)	(10,136)	(3,057)
Net (decrease) increase in cash and cash equivalents									1,441	(608)	1,916
Cash and cash equivalents, beginning of period				$ 6,034				$ 6,642	6,034	6,642	4,726
Cash and cash equivalents, end of period	$ 7,475				$ 6,034				$ 7,475	$ 6,034	$ 6,642