Supplemental Financial Information - Assets Held for Sale (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets, Current [Abstract]
Trade receivables, net	$ 7,307	$ 7,306
Materials and supplies	13,194	13,510
Prepaid expenses and other current assets	7,561	3,768
Property & equipment, net	100,903	87,441
Noncurrent deferred contract costs	20,095	4,196
Operating lease ROU asset	205	197
Other noncurrent assets	1,200	699
Assets held for sale	$ 150,465	$ 117,117