CESSATION OF MINING AT LEASED PUEBLO GRAVEL SITE (Details)		3 Months Ended				12 Months Ended
	Sep. 15, 2016 USD ($) T	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2016 USD ($)	Sep. 27, 2014 T	Dec. 29, 2018 USD ($)	Nov. 16, 2018 USD ($)
Disposition of assets
Charges related to cessation of mining an aggregates deposit						$ 6,840,000
Minimum
Disposition of assets
Quarterly royalty payment	$ 300,000
Pueblo Colorado gravel operations
Disposition of assets
Sand and gravel reserves (in tons) | T	50,000,000
Royalty overpayments	$ 1,470,000
Write off of prepaid royalties		$ 6,840,000	$ 6,840,000	$ 632,000
Recovery amount due pending outcome of litigation							$ 1,470,000
Charges related to cessation of mining an aggregates deposit						$ 627,000
Sand and gravel tons paid for | T					17,700,000
Pre payment of sand and gravel reserve | T					50,000,000