Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets:
Restricted assets	$ 1,762	$ 2,251
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Assets:
Restricted assets	1,762	2,251
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Restricted Assets - Capital Projects [Member]
Assets:
Restricted assets	848	1,348
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Restricted Assets - Landfill Closure [Member]
Assets:
Restricted assets	$ 914	903
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities:
Interest rate derivative		$ 178