That's probably not a withdrawal - it was moved by whoever owns the address, which the OP claims belongs to PrimeDice but it doesn't seem to be linked to any known PrimeDice wallets and there is no 14.2 BTC deposit to that address. I think the OP is not telling the whole story.
The 14.2 BTC was deposited to a different Primedice account with a different deposit address. I'll see if I can find that address. Like I said though they finally credited my account for that plus a bonus 0.9 BTC
14.2 BTC deposited to account with username 'glapattack'
9.8 BTC deposited to account with username 'gforce37'
I'm not sure why you are interested in the 14.2 BTC part, which doesn't seem relevant, but here are screen shot showing from my transaction log
you can see the TXID starts with '64336eb'
https://imgur.com/a/nRu6WiZbefore they issued the credit to my account:
https://imgur.com/a/UYtyH4xthen after they issued a credit of 15.1 BTC
https://imgur.com/a/ggi2AKH