Significant Accounting Policies and Recently Issued Accounting Standards - Summary of Property and Equipment (Detail)	9 Months Ended
	Sep. 30, 2018
Buildings and Improvements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	5 years
Buildings and Improvements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	40 years
Furniture, Fixtures and Other Equipment [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	2 years
Furniture, Fixtures and Other Equipment [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	10 years