XML 39 R28.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Federal Reserve Requirements | 12 Months Ended
--- | ---
Dec. 31, 2015
Federal Reserve Requirements [Abstract] |
Federal Reserve Requirements | 2 1.Federal Reserve Requirements During 2013, the Federal Reserve modified its structure for institutions to calculate their reserve requirements with the Reserve Bank. Under these new calculations, the Bank was not required to maintain certain cash reserve levels as its vault cash exceeded the levels for reserve.

X
- Definition The entire disclosure for required cash reserves with the Federal Reserve Bank. + References No definition available. + Details
Name: | func_FederalReserveRequirementsTextBlock
Namespace Prefix: | func_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RestrictedCashAndInvestmentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration