what offline wallet are you using? is it safe to store large amount there?
technically you can install all the desktop wallets on an offline computer to generate a bitcoin address/private key and send your bitcoins to that bitcoin address. and as long as you 1) downloaded the correct program and not a malicious one and 2) keep that computer offline and free of any malicious programs your coins are safe.
trezor that was suggested to you is good only if you have a lot of bitcoin and if you are willing to spend $100 for a bitcoin wallet.
Nice information re desktop wallets.
I have a Trezor and like it a lot. I agree that for any larger amounts of BTC, a proven hardware solution is best.
I use blockchain.info's wallet for convenience, but store the larger balance in a Trezor, Ledge Nano and Opendime.