Leases - Summary of Lease Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets
Operating lease assets	$ 288,406	$ 0
Finance lease assets	$ 3,864
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsMember
Total lease assets	$ 292,270
Liabilities
Operating lease liabilities	319,445	$ 0
Finance lease liabilities	$ 4,150
Finance Lease, Liability, Statement of Financial Position [Extensible List]	faf:NotesAndContractsPayableMember
Total lease liabilities	$ 323,595