Debt - Summary of Debt and Capital Lease Obligations (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total Debt	$ 1,674,792	$ 1,591,392
$200 Million Term Loan A [Member]
Debt Instrument [Line Items]
Total Debt	198,610	198,443
$500 Million Term Loan B [Member]
Debt Instrument [Line Items]
Total Debt	489,257	488,655
$350 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
Total Debt	347,138	346,660
$400 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
Total Debt	395,487	395,071
$700 Million Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total Debt	243,672	161,924
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Total Debt	$ 628	$ 639