Schedule of Useful Life of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
Land Improvements | Minimum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	5 years
Land Improvements | Maximum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	20 years
Building and Improvements | Minimum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	5 years
Building and Improvements | Maximum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	50 years
Equipment And Software | Minimum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	3 years
Equipment And Software | Maximum
Property, Plant and Equipment [Line Items]
Average number of useful life in years	10 years
Office Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Average number of useful life in years	5 years