Fair Value Disclosures - Contingent Consideration Liability Change in Amount (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	$ 501	$ 903
Contingent Consideration from New Acquisition	6,105	454	842
Payment of Contingent Consideration	(310)	0	0
Adjustment of Contingent Consideration	245	(856)
Ending Balance	6,541	501	903
Sterner Insurance Associates Inc [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	0
Contingent Consideration from New Acquisition	635
Payment of Contingent Consideration	0
Adjustment of Contingent Consideration	45
Ending Balance	680
Girard Partners [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	0
Contingent Consideration from New Acquisition	5,470
Payment of Contingent Consideration	0
Adjustment of Contingent Consideration	33
Ending Balance	5,503
John T Fretz Insurance Agency [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	501	0
Contingent Consideration from New Acquisition	0	454
Payment of Contingent Consideration	(310)	0
Adjustment of Contingent Consideration	167	47
Ending Balance	358	501
Javers Group [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance		903
Contingent Consideration from New Acquisition		0
Payment of Contingent Consideration		0
Adjustment of Contingent Consideration		(903)
Ending Balance		$ 0