Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions			3 Months Ended
	Feb. 17, 2017	Jan. 06, 2017	Mar. 31, 2018
Furniture, fixtures and office equipment
Depreciation And Other Amortization Expenses [Line Items]
Amount of divestiture of long-lived			$ 0.4
Land, Buildings and Improvements | California
Depreciation And Other Amortization Expenses [Line Items]
Amount of divestiture of long-lived		$ 17.3
Cash received from property, plant and equipment	$ 17.3
Net cash received from property, plant and equipment		16.7
Payments for commissions and other fees		$ 0.6