Debt - Annual Maturities of Long-Term Debt Excluding Capital Lease Obligations (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
2018	$ 5,000
2019	5,000
2020	5,000
2021	526,000
2022	205,000
Years thereafter	871,250
Total	1,617,250
$200 Million Term Loan A [Member]
Debt Instrument [Line Items]
2022	200,000
Total	200,000
$500 Million Term Loan B [Member]
Debt Instrument [Line Items]
2018	5,000
2019	5,000
2020	5,000
2021	5,000
2022	5,000
Years thereafter	471,250
Total	496,250
$350 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
2021	350,000
Total	350,000
$400 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
Years thereafter	400,000
Total	400,000
$700 Million Revolving Credit Facility [Member]
Debt Instrument [Line Items]
2021	171,000
Total	$ 171,000