Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Jan. 01, 2015	Dec. 31, 2014
ASSETS:
Intangible assets			$ 32,000
LIABILITIES:
Goodwill	$ 6,521	$ 6,521		$ 4,820
American Reliable Insurance Company
ASSETS:
Investments	226,458
Cash and cash equivalents	21,360
Premiums receivables, net	26,102
Accounts receivable	11,311
Reinsurance receivables	13,842
Prepaid reinsurance premiums	43,506
Intangible assets	32,000
Deferred federal income taxes	915
Other assets	6,473
Total assets	381,967
LIABILITIES:
Unearned premiums	172,234
Unpaid losses and loss adjustment expenses	89,489
Reinsurance balances payable	13,219
Contingent commissions	3,903
Other liabilities	5,026
Total liabilities	283,871
Estimated fair value of net assets acquired	98,096
Purchase price	99,797
Goodwill	$ 1,701