General - Title Losses and Related Claims (Details)	12 Months Ended
	Dec. 31, 2017 USD ($)
Reserve for Title Losses [Line Items]
Threshold amount for large claims	$ 1,000,000.0
Maximum
Reserve for Title Losses [Line Items]
Reserve amount, threshold percentage	5.00%
Minimum
Reserve for Title Losses [Line Items]
Reserve amount, threshold percentage	4.00%