Goodwill and Other Intangible Assets - Summary of Allocation of Acquisition Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite Lived Intangible Assets [Line Items]
Goodwill	$ 657,987	$ 650,237	$ 653,666
Amortizable intangibles, Gross carrying amount	382,312	377,086
Amortizable intangibles, Accumulated Amortization	145,868	109,827
Customer related intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Amortizable intangibles, Gross carrying amount	$ 187,717	$ 186,231
Amortizable intangibles, Weighted Average Amortization Period	15 years	15 years
Amortizable intangibles, Accumulated Amortization	$ 64,375	$ 51,491
Acquired software
Acquired Finite Lived Intangible Assets [Line Items]
Amortizable intangibles, Gross carrying amount	$ 179,466	$ 176,096
Amortizable intangibles, Weighted Average Amortization Period	7 years	7 years
Amortizable intangibles, Accumulated Amortization	$ 76,800	$ 55,115
Trade name
Acquired Finite Lived Intangible Assets [Line Items]
Amortizable intangibles, Gross carrying amount	$ 11,435	$ 11,065
Amortizable intangibles, Weighted Average Amortization Period	11 years	12 years
Amortizable intangibles, Accumulated Amortization	$ 3,768	$ 2,740
Leases acquired
Acquired Finite Lived Intangible Assets [Line Items]
Amortizable intangibles, Gross carrying amount	$ 3,694	$ 3,694
Amortizable intangibles, Weighted Average Amortization Period	10 years	9 years
Amortizable intangibles, Accumulated Amortization	$ 925	$ 481