Parent Company (Franklin Financial Services Corporation) Financial Information (Schedule Of Condensed Cash Flow 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
Adjustments to reconcile net income to net cash provided by operating activities:
Stock option compensation									74
Securities gains, net			$ 8	718	59	$ (20)	$ 221		8	280	33
OTTI loss on equity securities											50
Net cash provided by operating activities									13,679	14,356	15,397
Proceeds from sales of investment securities									1,381	5,421	5,188
Net cash used in investing activities									(49,557)	(12,942)	(3,556)
Dividends paid									(3,139)	(2,847)	(2,810)
Cash received from option exercises									92	59	52
Common stock issued under dividend reinvestment plan									1,246	923	926
Net cash provided by (used in) financing activities									26,451	6,434	(48,930)
(Decrease) increase in cash and cash equivalents									(9,427)	7,848	(37,089)
Cash and cash equivalents as of January 1				48,593				40,745	48,593	40,745	77,834
Cash and cash equivalents as of December 31	39,166				48,593				39,166	48,593	40,745
Franklin Financial Service Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									10,204	8,402	6,232
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed income of subsidiary									(10,391)	(7,708)	(4,185)
Stock option compensation									74
Securities gains, net										82	30
OTTI loss on equity securities											50
Decrease (increase) in other assets									(1,800)	(498)	321
Net cash provided by operating activities									1,687	1,110	1,746
Proceeds from sales of investment securities										568	312
Net cash used in investing activities										568	312
Dividends paid									(3,139)	(2,847)	(2,810)
Cash received from option exercises									92	59	52
Common stock issued under dividend reinvestment plan									1,246	923	926
Net cash provided by (used in) financing activities									(1,801)	(1,865)	(1,832)
(Decrease) increase in cash and cash equivalents									(114)	(187)	226
Cash and cash equivalents as of January 1				$ 414				$ 601	414	601	375
Cash and cash equivalents as of December 31	$ 300				$ 414				$ 300	$ 414	$ 601