Income Taxes - Deferred Income Taxes Related to Temporary Differences between Tax Bases of Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax liabilities:
Accelerated depreciation	$ 221,627	$ 208,539
Prepaid costs currently deductible	5,668	4,845
Other	5,011	4,703
Total deferred tax liabilities	232,306	218,087
Deferred tax assets:
Accrued costs not yet deductible	8,860	7,796
Allowance for doubtful accounts	486	486
Deferred revenues	2,512	1,774
Share-based compensation	2,178	1,367
Total deferred tax assets, net of valuation allowance of $0.2 million in 2019 and 2018	14,036	11,423
Deferred income taxes, net	$ 218,270	$ 206,664