Deposits (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
Time Deposits, $250,000 or More	$ 112,665	$ 92,527

The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more.

No definition available.

Name:	nwfl_TimeDeposits250000OrMore
Namespace Prefix:	nwfl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant