Debt - Summary of Debt and Capital Lease Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total Debt	$ 1,591,392	$ 1,502,554
$200 Million Term Loan A [Member]
Debt Instrument [Line Items]
Total Debt	198,443
$500 Million Term Loan B [Member]
Debt Instrument [Line Items]
Total Debt	488,655
$400 Million Term Loan B [Member]
Debt Instrument [Line Items]
Total Debt		384,727
$350 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
Total Debt	346,660	345,754
$400 Million 5% Senior Notes [Member]
Debt Instrument [Line Items]
Total Debt	395,071	394,281
$700 Million Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total Debt	161,924	377,133
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Total Debt	$ 639	$ 659