Reserve for Known and Incurred but Not Reported Claims (Summary of Loss Reserves) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Known title claims, amount	$ 80,306	$ 83,094
IBNR title claims, amount	877,134	875,724
Total title claims, amount	957,440	958,818
Non-title claims, amount	85,239	70,115
Total loss reserves, amount	$ 1,042,679	$ 1,028,933	$ 1,025,863	$ 983,880
Known title claims, percent	7.70%	8.10%
IBNR title claims, percent	84.10%	85.10%
Total title claims, percent	91.80%	93.20%
Non-title claims, percent	8.20%	6.80%
Total loss reserves, percent	100.00%	100.00%