Description of Business and Summary of Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Segment Customer	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	May. 16, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of reportable segment | Segment	1
Common stock dividend				50.00%
Common stock split	Three-for-two
Deferred tax assets reclassified to noncurrent liabilities	$ 19.5
Depreciation	63.4	$ 58.4	$ 51.0
Primary payroll-related costs capitalized	$ 2.2	1.0	2.1
Stock-based awards compensation expense amortization period	3 years
Number of customers | Customer	0
Percentage of consolidated operating revenue	6.00%
Advertising costs	$ 1.7	$ 1.9	$ 0.8