Indebtedness - Early Extinguishment of Debt - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
5.00% Senior Notes Due 2022
Debt Instrument [Line Items]
Extinguishment of debt, principal amount	$ 32.9
Interest rate on notes	5.00%	5.00%
5.875% Senior Notes Due 2022
Debt Instrument [Line Items]
Extinguishment of debt, principal amount	$ 6.2
Interest rate on notes	5.875%	5.875%
5.75% Senior Notes Due 2021
Debt Instrument [Line Items]
Extinguishment of debt, principal amount	$ 54.5
Interest rate on notes	5.75%	5.75%