Business Segment Information - Operating Statements (Details) - USD ($)	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Income
Interest income	$ 42,471,000	$ 33,250,000	$ 33,489,000	$ 33,449,000	$ 35,378,000	$ 34,610,000	$ 31,980,000	$ 27,877,000		$ 142,659,000	$ 129,845,000	$ 106,911,000
Total interest expense	3,242,000	2,625,000	2,573,000	2,407,000	2,318,000	2,159,000	1,816,000	1,529,000		10,847,000	7,822,000	5,387,000
Net interest income	39,229,000	30,625,000	30,916,000	31,042,000	33,060,000	32,451,000	30,164,000	26,348,000		131,812,000	122,023,000	101,524,000
Provision for loan losses	3,223,000	(576,000)	(740,000)	(1,061,000)	142,000	(425,000)	7,198,000	506,000		846,000	7,421,000	99,000
Net interest income after provision	36,006,000	31,201,000	31,656,000	32,103,000	32,918,000	32,876,000	22,966,000	25,842,000		130,966,000	114,602,000	101,425,000
Noninterest income	2,393,000	2,618,000	2,765,000	2,468,000	2,393,000	2,206,000	2,780,000	2,195,000		10,244,000	9,574,000	9,612,000
Noninterest expense	30,626,000	17,909,000	18,445,000	17,918,000	16,941,000	17,728,000	24,862,000	15,990,000		84,898,000	75,521,000	60,738,000
Income before income taxes	7,773,000	15,910,000	15,976,000	16,653,000	18,370,000	17,354,000	884,000	12,047,000		56,312,000	48,655,000	50,299,000
Income tax expense	2,088,000	4,633,000	4,623,000	4,507,000	5,138,000	4,979,000	(31,000)	3,238,000		15,851,000	13,324,000	26,471,000
Net income	5,685,000	11,277,000	11,353,000	$ 12,146,000	13,232,000	12,375,000	915,000	8,809,000		40,461,000	35,331,000	23,828,000
Total assets	4,109,463,000				3,096,562,000				$ 2,843,452,000	4,109,463,000	3,096,562,000	2,843,452,000
Loans, net of deferred fees	2,533,844,000				1,886,405,000				1,582,667,000	2,533,844,000	1,886,405,000	1,582,667,000
Goodwill	167,420,000				83,753,000				45,664,000	167,420,000	83,753,000	45,664,000
Business Combination, Acquisition Related Costs	9,879,000	661,000	540,000		139,000	199,000	8,214,000	615,000		11,080,000	9,167,000	671,000
Pre-tax acquisition costs	9,879,000	$ 661,000	$ 540,000		139,000	$ 199,000	$ 8,214,000	$ 615,000		11,080,000	9,167,000	671,000
Tax Cuts and Jobs Act of 2017 effect on re-measurement of net deferred tax assets									7,103,000			7,103,000
Banking
Operating Income
Interest income										130,971,000	115,147,000	95,027,000
Intersegment interest allocations										1,182,000	1,856,000	1,126,000
Total interest expense										10,847,000	7,822,000	5,387,000
Net interest income										121,306,000	109,181,000	90,766,000
Provision for loan losses										517,000	7,224,000	102,000
Net interest income after provision										120,789,000	101,957,000	90,664,000
Noninterest income										9,643,000	8,662,000	8,559,000
Noninterest expense										78,159,000	69,164,000	53,860,000
Intersegment expense allocations										547,000	753,000	528,000
Income before income taxes										52,820,000	42,208,000	45,891,000
Income tax expense										14,819,000	11,418,000	24,266,000
Net income										38,001,000	30,790,000	21,625,000
Total assets	4,045,801,000				3,028,721,000				2,780,286,000	4,045,801,000	3,028,721,000	2,780,286,000
Loans, net of deferred fees	2,487,864,000				1,832,815,000				1,533,841,000	2,487,864,000	1,832,815,000	1,533,841,000
Goodwill	154,376,000				70,709,000				32,620,000	154,376,000	70,709,000	32,620,000
Business Combination, Acquisition Related Costs										11,080,000	9,167,000
Pre-tax acquisition costs										11,080,000	9,167,000
Tax Cuts and Jobs Act of 2017 effect on re-measurement of net deferred tax assets												6,749,000
Factoring
Operating Income
Interest income										11,688,000	14,698,000	11,884,000
Intersegment interest allocations										(1,182,000)	(1,856,000)	(1,126,000)
Net interest income										10,506,000	12,842,000	10,758,000
Provision for loan losses										329,000	197,000	(3,000)
Net interest income after provision										10,177,000	12,645,000	10,761,000
Noninterest income										601,000	912,000	1,053,000
Noninterest expense										6,739,000	6,357,000	6,878,000
Intersegment expense allocations										(547,000)	(753,000)	(528,000)
Income before income taxes										3,492,000	6,447,000	4,408,000
Income tax expense										1,032,000	1,906,000	2,205,000
Net income										2,460,000	4,541,000	2,203,000
Total assets	63,662,000				67,841,000				63,166,000	63,662,000	67,841,000	63,166,000
Loans, net of deferred fees	45,980,000				53,590,000				48,826,000	45,980,000	53,590,000	48,826,000
Goodwill	13,044,000				13,044,000				$ 13,044,000	13,044,000	13,044,000	13,044,000
Tax Cuts and Jobs Act of 2017 effect on re-measurement of net deferred tax assets												354,000
HCC (Parent)
Operating Income
Total interest expense										2,314,000	2,315,000	1,394,000
Income before income taxes										17,223,000	11,655,000	12,450,000
Income tax expense										(1,481,000)	(1,515,000)	(1,300,000)
Net income										40,461,000	35,331,000	23,828,000
Total assets	$ 616,889,000				$ 407,068,000					$ 616,889,000	$ 407,068,000
Tri Valley Bank and United American Bank | Banking
Operating Income
Business Combination, Acquisition Related Costs												671,000
Pre-tax acquisition costs												$ 671,000