Cash Flow Information - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Other Significant Noncash Transactions [Line Items]
Cash paid for interest		$ 27.2	$ 33.9
Net of capitalized interest		3.1	1.4
Line of credit facilities gross borrowings		202.0	200.0
Line of credit facilities gross repayments		$ 297.0	$ 180.0
Noncash Investing and Financing Activities Related Text	A $150.0 million paydown of the 2013 Revolving Facility was made in the six months ended June 30, 2017, which was directly paid from the 2014 7-Year Term Loan additional borrowing and is considered to be a non-cash transaction.