Reserve for Known and Incurred but Not Reported Claims (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Payments, net of recoveries, related to: Current year	$ 35,000	$ 209,845	$ 196,656	$ 182,653
Payments, net of recoveries, related to: Prior years		266,647	$ 273,094	$ 296,657
Recoveries on reinsured losses related to large commercial title claim		$ 23,800
Provision for title loss, percentage of title premiums and escrow fees		6.60%	7.10%	8.90%
Ultimate loss rate		4.20%	5.30%	5.00%
Estimated increase in loss reserve for prior policy years		$ 93,100	$ 64,100	$ 150,200
Ultimate loss in excess		2,500
IBNR reserve		844,364	$ 802,069
Reasonable estimates of IBNR reserve range limit minimum		77,600
Reasonable estimates of IBNR reserve range limit maximum		$ 124,900
Projected ultimate loss ratio percentage		4.20%	4.70%	3.70%
Known title claims, amount		$ 87,543	$ 165,330
Decline in reserve for known title claims, amount		$ 77,800
Decline in reserve for known title claims, percentage		47.00%
Amount recovered through reinsurance	$ 21,000
Known title large claims
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Known title claims, amount			56,000
Domestic Commercial Policies
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Estimated increase in loss reserve for prior policy years			41,400
Domestic Lender
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Estimated increase in loss reserve for prior policy years				$ 67,400
Commercial Policies
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Estimated increase in loss reserve for prior policy years				38,800
Guaranteed Valuation Product
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Estimated increase in loss reserve for prior policy years				21,700
Minimum
Reserve For Known And Incurred But Not Reported Claims [Line Items]
IBNR reserve		$ 719,500
Maximum
Reserve For Known And Incurred But Not Reported Claims [Line Items]
IBNR reserve		922,000
Specialty Insurance
Reserve For Known And Incurred But Not Reported Claims [Line Items]
Payments, net of recoveries, related to: Current year		198,600	174,400	167,300
Payments, net of recoveries, related to: Prior years		$ 23,100	$ 23,200	$ 16,000