Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net interest income	$ 37,316	$ 27,965	$ 74,755	$ 55,368
Provision for loan and lease losses	3,137	(83)	4,167	208
Net interest income after provision for loan and lease losses	34,179	28,048	70,588	55,160
Fees for wealth management services	10,658	9,807	20,966	19,110
Insurance commissions	1,902	943	3,595	1,706
Capital markets revenue	2,105	953	2,771	953
Service charges on deposit accounts	752	630	1,465	1,277
Loan servicing and other fees	475	519	1,161	1,022
Net gain on sale of loans	528	520	1,046	1,149
Net gain on sale of investment securities available for sale			7	1
Net gain (loss) on sale of OREO	111	(12)	287	(12)
Other operating income	3,544	1,425	8,313	2,806
Total noninterest income	20,075	14,785	39,611	28,012
Salaries and wages	16,240	13,580	32,222	26,030
Employee benefits	2,877	2,404	6,585	4,893
Occupancy and bank premises	2,697	2,247	5,747	4,773
Amortization of intangible assets	889	687	1,768	1,380
Professional fees	932	1,049	1,680	1,760
Other operating expenses	12,201	8,528	23,864	16,319
Total noninterest expenses	35,836	28,495	71,866	55,155
Segment profit	18,418	14,338	38,333	28,017
Intersegment (revenues) expenses	0	0	0	0
Pre-tax segment profit after eliminations	$ 18,418	$ 14,338	$ 38,333	$ 28,017
% of segment pre-tax profit after eliminations	100.00%	100.00%	100.00%	100.00%
Segment assets	$ 4,394,203	$ 3,438,000	$ 4,394,203	$ 3,438,000	$ 4,449,720
Assets under management, administration, supervision and brokerage	13,404,700		13,404,700		$ 12,968,700
Banking
Segment Reporting Information [Line Items]
Net interest income	37,315	27,964	74,753	55,366
Provision for loan and lease losses	3,137	(83)	4,167	208
Net interest income after provision for loan and lease losses	34,178	28,047	70,586	55,158
Fees for wealth management services	0	0	0	0
Insurance commissions	0	0	0	0
Capital markets revenue	2,105	953	2,771	953
Service charges on deposit accounts	752	630	1,465	1,277
Loan servicing and other fees	475	519	1,161	1,022
Net gain on sale of loans	528	520	1,046	1,149
Net gain on sale of investment securities available for sale			7	1
Net gain (loss) on sale of OREO	111	(12)	287	(12)
Other operating income	3,486	1,376	8,211	2,709
Total noninterest income	7,457	3,986	14,948	7,099
Salaries and wages	11,184	9,284	22,340	17,915
Employee benefits	1,922	1,421	4,598	2,978
Occupancy and bank premises	2,235	1,849	4,811	3,976
Amortization of intangible assets	385	196	783	392
Professional fees	879	1,031	1,608	1,712
Other operating expenses	10,875	7,489	21,306	14,254
Total noninterest expenses	27,480	21,270	55,446	41,227
Segment profit	14,155	10,763	30,088	21,030
Intersegment (revenues) expenses	(150)	(112)	(299)	(224)
Pre-tax segment profit after eliminations	$ 14,005	$ 10,651	$ 29,789	$ 20,806
% of segment pre-tax profit after eliminations	76.00%	74.30%	77.70%	74.30%
Segment assets	$ 4,339,300	$ 3,387,000	$ 4,339,300	$ 3,387,000
Wealth Management
Segment Reporting Information [Line Items]
Net interest income	1	1	2	2
Provision for loan and lease losses	0	0	0	0
Net interest income after provision for loan and lease losses	1	1	2	2
Fees for wealth management services	10,658	9,807	20,966	19,110
Insurance commissions	1,902	943	3,595	1,706
Capital markets revenue	0	0	0	0
Service charges on deposit accounts	0	0	0	0
Loan servicing and other fees	0	0	0	0
Net gain on sale of loans	0	0	0	0
Net gain on sale of investment securities available for sale			0	0
Net gain (loss) on sale of OREO	0	0	0	0
Other operating income	58	49	102	97
Total noninterest income	12,618	10,799	24,663	20,913
Salaries and wages	5,056	4,296	9,882	8,115
Employee benefits	955	983	1,987	1,915
Occupancy and bank premises	462	398	936	797
Amortization of intangible assets	504	491	985	988
Professional fees	53	18	72	48
Other operating expenses	1,326	1,039	2,558	2,065
Total noninterest expenses	8,356	7,225	16,420	13,928
Segment profit	4,263	3,575	8,245	6,987
Intersegment (revenues) expenses	150	112	299	224
Pre-tax segment profit after eliminations	$ 4,413	$ 3,687	$ 8,544	$ 7,211
% of segment pre-tax profit after eliminations	24.00%	25.70%	22.30%	25.70%
Segment assets	$ 54,900	$ 51,000	$ 54,900	$ 51,000