Business Segments (Statement of Operations and Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 33,858	$ 33,111	$ 68,442	$ 64,963
Provision for loan losses	525	400	1,175	400
Net interest income after provision for loan losses	33,333	32,711	67,267	64,563
Noninterest income	16,753	15,993	32,120	31,736
Depreciation and amortization expense	1,074	1,050	2,150	2,125
Other noninterest expenses related to segments	27,077	25,238	52,965	51,293
Total noninterest expense	28,151	26,288	55,115	53,418
Income before income taxes	21,935	22,416	44,272	42,881
Income tax expense	4,662	4,742	9,504	8,996
Net income	17,273	17,674	34,768	33,885
Total assets	5,189,672	4,737,242	5,189,672	4,737,242	$ 5,010,766
Expenditures for long-lived assets	316	864	1,971	1,675
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	27,867	26,644	55,169	52,620
Provision for loan losses	525	400	1,175	400
Net interest income after provision for loan losses	27,342	26,244	53,994	52,220
Noninterest income	6,690	5,837	12,146	10,773
Depreciation and amortization expense	672	637	1,342	1,274
Other noninterest expenses related to segments	16,660	15,509	32,421	30,975
Total noninterest expense	17,332	16,146	33,763	32,249
Income before income taxes	16,700	15,935	32,377	30,744
Income tax expense	3,603	3,387	7,024	6,490
Net income	13,097	12,548	25,353	24,254
Total assets	3,916,915	3,647,649	3,916,915	3,647,649
Expenditures for long-lived assets	297	801	1,597	1,252
Wealth Management Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	(120)	(77)	(247)	(135)
Provision for loan losses	0	0	0	0
Net interest income after provision for loan losses	(120)	(77)	(247)	(135)
Noninterest income	9,557	9,602	18,808	19,875
Depreciation and amortization expense	363	370	729	766
Other noninterest expenses related to segments	6,937	6,593	13,414	13,792
Total noninterest expense	7,300	6,963	14,143	14,558
Income before income taxes	2,137	2,562	4,418	5,182
Income tax expense	582	655	1,199	1,298
Net income	1,555	1,907	3,219	3,884
Total assets	77,757	68,009	77,757	68,009
Expenditures for long-lived assets	0	11	292	313
Corporate [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	6,111	6,544	13,520	12,478
Provision for loan losses	0	0	0	0
Net interest income after provision for loan losses	6,111	6,544	13,520	12,478
Noninterest income	506	554	1,166	1,088
Depreciation and amortization expense	39	43	79	85
Other noninterest expenses related to segments	3,480	3,136	7,130	6,526
Total noninterest expense	3,519	3,179	7,209	6,611
Income before income taxes	3,098	3,919	7,477	6,955
Income tax expense	477	700	1,281	1,208
Net income	2,621	3,219	6,196	5,747
Total assets	1,195,000	1,021,584	1,195,000	1,021,584
Expenditures for long-lived assets	$ 19	$ 52	$ 82	$ 110