Anytime you /whois <Nick> on a server, if they are on the same server as you are, then the same server know their idle time.
But if they are on a different server, than the server *you're* connected on, does not know their idle time. So you have to contact their server, by typing /whois <Nick> <Nick>.
So in your alias.
/whois /whois $$1 $$1
Then /whois nick and you will always get their idle time except for on ConferenceRoom IRCds.
But I use /w for /whois.
-Neal.
