There are always 30+ idlers, except when a large amount of dumping is required.
Sounds like a military waiting to happen. Have you ever had an Elite Wrestler? Now's your chance.
Honestly though, more idlers means a more efficient fortress, in general. You have [n] dwarves doing the work of [n+30] dwarves. If your fort was less efficient, you'd have more people hauling and dumping things, and thus fewer idlers.
Another thing I need to figure out is how to get a steady supply of booze. I can never manage to have the barrel/pot generation and booze production equal the demand, especially when the pots and barrels are constantly being filled with fish, meat, and plants.
First thing I'd say is stop producing so much. Reassign some of your butchers/fishers/farmers to stonecrafting or woodcrafting until you have enough pots*, then assign them one or two at a time to the military until your supplies balance out.
Second thing I'd say is figure out the 'workflow' plugin of DFHack and use it profusely. I think I say that in every production-related thread, but seriously: the plugin allows you to tell your dwarves "when the supply of [insert object/supply here] drops below a certain level, begin producing it until it reaches the maximum I give you." Which means you can set a workflow order on your Brew Drink job to keep the number of available drinks reasonable for the number of dwarves you have; e.g. if you have 100 dwarves and want drinks available for a third to half of them at a time, you can set workflow to keep between 35-50 stacks of beverage available. When the drink stack count drops to 34 available stacks, the plugin starts up your Brew Drinks until you have 50 again. That way you only ever have a maximum of 50 barrels/pots tied up with drinks, (plus the negligible number in use at the time the available ones reach your limit) leaving the rest for your other foods. Likewise you can put a workflow order on your Make Barrel or Make Rock Pot jobs and your dwarves can keep 10-15 pots (or whatever number you like) available, without flooding your fort with empty containers.