General (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($) reporting_unit	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Accounting Policies [Abstract]
Revenue major segments percentage	48.00%
Method for estimating unreported policy revenues, period of use (more than) (years)	10 years
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Threshold amount for large claims	$ 1,000,000.0
Number of reporting units used for goodwill evaluation | reporting_unit	4
Non-cancelable operating lease, expiration period (years)	10 years
Unrecognized excess tax benefits from additional paid-in capital to retained earnings	$ (631,000)	$ 0	$ 0
Minimum
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Threshold percentage, reserve amount (percent)	4.00%
Intangible assets estimated life (years)	3 years
Minimum | Buildings
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life (years)	30 years
Minimum | Furniture and equipment
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life (years)	3 years
Maximum
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Threshold percentage, reserve amount (percent)	5.00%
Intangible assets estimated life (years)	10 years
Maximum | Buildings
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life (years)	40 years
Maximum | Furniture and equipment
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful life (years)	10 years
Accounting Standards Update 2016-09, Forfeiture Rate Component | Retained Earnings | New Accounting Pronouncement, Early Adoption, Effect
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Unrecognized excess tax benefits from additional paid-in capital to retained earnings	$ (600,000)
Accounting Standards Update 2016-09, Forfeiture Rate Component | Additional paid-in capital | New Accounting Pronouncement, Early Adoption, Effect
Organization Consolidation And Summary Of Significant Accounting Policies [Line Items]
Unrecognized excess tax benefits from additional paid-in capital to retained earnings	$ 600,000