Industry Segment Information (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
Fee revenue and other income:
Fee income from customers		$ 27,372	$ 25,640	$ 54,385	$ 51,014
Interest income	[1]	13,858	12,137	27,296	24,113
Interest expense		1,305	794	2,595	1,473
Intersegment income (expense)
Tax-equivalized pre-tax income	[1]	9,954	9,520	20,403	20,008
Goodwill		12,569	12,569	12,569	12,569	$ 12,569
Other intangible assets, net		1,345	1,775	1,345	1,775
Total assets		1,728,684	1,570,305	1,728,684	1,570,305	$ 1,695,176
Average funding sources		1,221,211	1,170,524	$ 1,229,952	$ 1,205,441
Tax-equivalent basis tax rate				21.00%	21.00%
Tax-equivalent adjustment		531	624	$ 1,072	$ 1,311
Information Services [Member]
Fee revenue and other income:
Fee income from customers		27,227	25,262	54,023	50,134
Interest income	[1]	6,336	6,017	12,513	12,175
Interest expense
Intersegment income (expense)
Tax-equivalized pre-tax income	[1]	6,791	6,750	14,378	14,125
Goodwill		12,433	12,433	12,433	12,433
Other intangible assets, net		1,345	1,775	1,345	1,775
Total assets		934,620	807,571	934,620	807,571
Average funding sources		650,231	617,287	648,918	631,022
Banking Services [Member]
Fee revenue and other income:
Fee income from customers		392	318	783	694
Interest income	[1]	7,666	6,795	15,152	13,690
Interest expense		1,305	794	2,595	1,473
Intersegment income (expense)		535	486	1,054	948
Tax-equivalized pre-tax income	[1]	3,555	3,385	6,815	7,449
Goodwill		136	136	136	136
Other intangible assets, net
Total assets		816,661	806,560	816,661	806,560
Average funding sources		570,980	553,237	581,034	574,419
Corporate Eliminations and Other [Member]
Fee revenue and other income:
Fee income from customers		(247)	60	(421)	186
Interest income	[1]	(144)	(675)	(369)	(1,752)
Interest expense
Intersegment income (expense)		(535)	(486)	(1,054)	(948)
Tax-equivalized pre-tax income	[1]	(392)	(615)	(790)	(1,566)
Goodwill
Other intangible assets, net
Total assets		(22,597)	(43,826)	(22,597)	(43,826)
Average funding sources

[1] Presented on a tax-equivalent basis assuming a tax rate of 21% for both 2019 and 2018. The tax-equivalent adjustment was approximately $531,000 and $624,000 for the Second Quarter of 2019 and 2018, respectively, and $1,072,000 and $1,311,000 for the First Half of 2019 and 2018, respectively.