Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 36,000	$ 36,400	$ 10,300
Amortization expense, 2018	35,278
Amortization expense, 2019	33,920
Amortization expense, 2020	32,495
Amortization expense, 2021	32,136
Amortization expense, 2022	28,665
Leases acquired
Finite-Lived Intangible Assets [Line Items]
Amortization expense, 2018	425
Amortization expense, 2019	373
Amortization expense, 2020	313
Amortization expense, 2021	312
Amortization expense, 2022	312
Amortization expense, thereafter	$ 1,000