Leases - Summary of Future Minimum Lease and Royalty Commitments for all Noncancelable Agreements and Capital Lease Obligations (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
2019		$ 3,718
2020	$ 3,243	2,695
2021	1,951	1,735
2022	1,094	1,004
2023	779	713
Thereafter	4,176	3,893
Total lease payments	14,199	13,758
Less: imputed interest	(2,881)	(2,879)
Total finance lease liabilities	11,318	10,879
Less: current lease obligations	(3,456)	(3,249)
Other noncurrent liabilities	7,862	7,630
2019		105,955
2020	63,870	70,478
2021	52,674	60,382
2022	48,376	57,531
2023	45,912	56,511
Thereafter	429,013	318,147
Total lease payments	$ 692,859	669,004
2019		14,614
2020		11,364
2021		10,335
2022		9,545
2023		8,109
Thereafter		65,981
Total		$ 119,948