Investment in Variable Interest Entity - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Earnings (loss) in equity of unconsolidated affiliate	$ (1.0)
Trade receivables	3.3
Other assets	$ 0.3	$ 0.2
PHIC's date of incorporation	May 26, 2011
PHI Century Limited [Member]
Variable Interest Entity [Line Items]
Investment in the common stock	49.00%