Annual report pursuant to Section 13 and 15(d)

Commitment and Contingencies - Additional Information (Detail)

v3.8.0.1
Commitment and Contingencies - Additional Information (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2017
USD ($)
Commitment And Contingencies [Line Items]  
Expansion and enhancement contracts $ 32.8
New Jersey [Member]  
Commitment And Contingencies [Line Items]  
Settlement agreement, amount 8.0
Settlement agreement, amount after tax $ 6.0