Parent Company (Franklin Financial Services Corporation) Financial Information (Schedule Of Condensed Comprehensive Income Statement) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income		$ 2,267	$ 2,579	$ 2,474	$ 2,884	$ 1,847	$ 2,410	$ 2,319	$ 1,826	$ 10,204	$ 8,402	$ 6,232
Securities:
Unrealized (losses) gains arising during the period	[1]									(498)	3,353	(3,326)
Reclassification adjustment for (gains) losses included in net income	[1]									(716)	(260)	42
Net unrealized (losses) gains	[1]									(1,214)	3,093	(3,284)
Tax effect	[1]									413	(1,052)	1,117
Net of tax amount	[1]									(801)	2,041	(2,167)
Total other comprehensive (loss) income of Parent										(622)	1,596	(646)
Franklin Financial Service Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net income										10,204	8,402	6,232
Securities:
Unrealized (losses) gains arising during the period											(236)	425
Reclassification adjustment for (gains) losses included in net income											(82)	20
Net unrealized (losses) gains											(318)	445
Tax effect											108	(151)
Net of tax amount											(210)	294
Total other comprehensive (loss) income of Parent											(210)	294
Other comprehensive (loss) income of subsidiaries										(622)	1,806	(940)
Total Comprehensive Income										$ 9,582	$ 9,998	$ 5,586

[1] Securities / gain on conversion & securities (gains) losses, net $243, $88, and $14 for years ended December 31, 2015, 2014, and 2013, respectively.