Impairment of Long-Lived Assets - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018
Impairment Or Disposal Of Tangible Assets Disclosure [Abstract]
Estimated aggregate fair value of long-lived assets impaired during current period	$ 23,037
Multiple of cash flows used to estimate fair value of long-lived asset	6.5	6.5