Annual report pursuant to Section 13 and 15(d)

Derivative Instruments - Additional Information (Detail)

v3.8.0.1
Derivative Instruments - Additional Information (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2017
USD ($)
Derivative Instruments And Hedging Activities Disclosure [Abstract]  
Interest rate swap agreement date Aug. 12, 2015
Cash flow hedge, variable rate debt $ 70.0
Derivative notional amount $ 66.6
Maturity date of swap agreement Aug. 12, 2022
Weighted-average fixed rate 2.08%
Derivative instrument interest rate description 30-day LIBOR rate
Derivative, fixed interest rate 4.08%