Business Segment Information - Operating Statements (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Operating Income
Interest income	$ 31,980,000	$ 26,107,000	$ 59,857,000	$ 50,804,000
Total interest expense	1,816,000	1,174,000	3,345,000	2,045,000
Net interest income	30,164,000	24,933,000	56,512,000	48,759,000
Provision (credit) for loan losses	7,198,000	(46,000)	7,704,000	275,000
Net interest income after provision	22,966,000	24,979,000	48,808,000	48,484,000
Noninterest income	2,780,000	2,293,000	4,975,000	4,588,000
Noninterest expense	24,862,000	15,254,000	40,852,000	30,582,000
Income before income taxes	884,000	12,018,000	12,931,000	22,490,000
Income tax expense	(31,000)	4,569,000	3,207,000	8,503,000
Net income	915,000	7,449,000	9,724,000	13,987,000
Total assets	3,123,207,000	2,732,900,000	3,123,207,000	2,732,900,000	$ 2,843,452,000
Loans, net of deferred fees	1,956,633,000	1,566,324,000	1,956,633,000	1,566,324,000	1,582,667,000
Goodwill	84,417,000	45,664,000	84,417,000	45,664,000	$ 45,664,000
Business Combination One time pre-tax severance, retention, acquisition and integration costs	8,214,000		8,829,000
Banking
Operating Income
Interest income	28,625,000	23,372,000	53,356,000	45,341,000
Intersegment interest allocations	376,000	242,000	703,000	502,000
Total interest expense	1,816,000	1,174,000	3,345,000	2,045,000
Net interest income	27,185,000	22,440,000	50,714,000	43,798,000
Provision (credit) for loan losses	7,141,000	(46,000)	7,629,000	265,000
Net interest income after provision	20,044,000	22,486,000	43,085,000	43,533,000
Noninterest income	2,531,000	1,937,000	4,617,000	4,052,000
Noninterest expense	23,301,000	13,424,000	37,768,000	27,003,000
Intersegment expense allocations	227,000	129,000	402,000	262,000
Income before income taxes	(499,000)	11,128,000	10,336,000	20,844,000
Income tax expense	(440,000)	4,196,000	2,440,000	7,812,000
Net income	(59,000)	6,932,000	7,896,000	13,032,000
Total assets	3,044,221,000	2,676,599,000	3,044,221,000	2,676,599,000
Loans, net of deferred fees	1,893,147,000	1,523,928,000	1,893,147,000	1,523,928,000
Goodwill	71,373,000	32,620,000	71,373,000	32,620,000
Business Combination One time pre-tax severance, retention, acquisition and integration costs	8,214,000		8,829,000
Factoring
Operating Income
Interest income	3,355,000	2,735,000	6,501,000	5,463,000
Intersegment interest allocations	(376,000)	(242,000)	(703,000)	(502,000)
Net interest income	2,979,000	2,493,000	5,798,000	4,961,000
Provision (credit) for loan losses	57,000		75,000	10,000
Net interest income after provision	2,922,000	2,493,000	5,723,000	4,951,000
Noninterest income	249,000	356,000	358,000	536,000
Noninterest expense	1,561,000	1,830,000	3,084,000	3,579,000
Intersegment expense allocations	(227,000)	(129,000)	(402,000)	(262,000)
Income before income taxes	1,383,000	890,000	2,595,000	1,646,000
Income tax expense	409,000	373,000	767,000	691,000
Net income	974,000	517,000	1,828,000	955,000
Total assets	78,986,000	56,301,000	78,986,000	56,301,000
Loans, net of deferred fees	63,486,000	42,396,000	63,486,000	42,396,000
Goodwill	$ 13,044,000	$ 13,044,000	$ 13,044,000	$ 13,044,000