Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2015
Income Tax Disclosure [Line Items]
U.S. federal statutory income tax rate			35.00%	35.00%	35.00%
Dividends received from Kronos Worldwide, Inc.			$ 21,132	$ 21,132	$ 21,132
Adjustment to the reserve for uncertain tax positions, net	$ 3,000
Benefit over effective income tax rate			12,200	15,200	15,200
Canadian Income Tax Audit
Income Tax Disclosure [Line Items]
Adjustment to the reserve for uncertain tax positions, net		$ 3,000
U.S. Income Tax Audit
Income Tax Disclosure [Line Items]
Adjustment to the reserve for uncertain tax positions, net		$ 3,100
Kronos
Income Tax Disclosure [Line Items]
Dividends received from Kronos Worldwide, Inc.			21,100	$ 21,100	$ 21,100
Deferred income tax asset valuation allowance			$ 8,700			$ 150,300