Derivatives used as Hedging Instruments (Details)	Jun. 30, 2016 $ / Ounce-oz
Gold zero cost collars:
Floor amount (ounces)	6,000
Average floor price	1,100
Ceiling amount (ounces)	6,000
Average ceiling price	1,320

The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

No definition available.

Name:	us-gaap_DerivativeAverageFloorPrice
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant