Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Amortization expense of finite life intangible assets	$ 2,200	$ 2,400	$ 4,320	$ 4,988
Amortization expense of finite life intangibles for 2019	4,100		4,100
Amortization expense of finite life intangibles for 2020	6,800		6,800
Amortization expense of finite life intangibles for 2021	5,700		5,700
Amortization expense of finite life intangibles for 2022	4,800		4,800
Amortization expense of finite life intangibles for 2023	4,000		4,000
Finite lived intangible assets	35,527	$ 42,444	35,527	$ 42,444	$ 35,959	$ 49,956
Certain Tradenames [Member]
Schedule Of Goodwill And Other Intangible Assets [Line Items]
Finite lived intangible assets	$ 3,900		$ 3,900
Finite lived intangible assets, useful life			10 years