Estimated title losses - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Gain (Loss) on Investments [Line Items]
Ultimate loss rate for policies issued in current year	3.60%	3.80%	5.10%
Net increase in loss reserve estimates for prior years	$ 38,236	$ 16,728	$ 14,275
Recorded provisions	106,265	81,305	106,318
Change in prior years reserve, claims payment experience
Gain (Loss) on Investments [Line Items]
Net increase in loss reserve estimates for prior years	6,200
Recorded provisions		17,900	7,600
Change in prior years reserve, large title claims
Gain (Loss) on Investments [Line Items]
Net increase in loss reserve estimates for prior years	29,100
Recorded provisions	$ 31,700	$ 3,100	$ 28,800