Fair Value of Financial Instruments - Carrying Value and Fair Value of Long-Term Debt (Parenthetical) (Detail)	Sep. 30, 2019	Jul. 01, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percent on aggregate principal amount of outstanding		1.25%
2.40% Term Loan, Due Jun. 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percent on aggregate principal amount of outstanding	2.40%		2.40%
2.05% Term Loan, Due Mar. 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percent on aggregate principal amount of outstanding	2.05%		2.05%
1.30% Term Loan, Due Jun. 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percent on aggregate principal amount of outstanding	1.30%		1.30%
1.55% Term Loan, Due Sep. 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Percent on aggregate principal amount of outstanding	1.55%		1.55%