Fair Value Disclosures - Contingent Consideration Liability Change in Amount (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	$ 6,541	$ 501
Contingent Consideration from New Acquisition	1,525	6,105	$ 454
Payment of Contingent Consideration	(2,631)	(310)	0
Adjustment of Contingent Consideration	142	245
Ending Balance	5,577	6,541	501
Sterner Insurance Associates Inc [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	680	0
Contingent Consideration from New Acquisition	1,525	635
Payment of Contingent Consideration	(1,751)	0
Adjustment of Contingent Consideration	690	45
Ending Balance	1,144	680	0
Girard Partners [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	5,503	0
Contingent Consideration from New Acquisition	0	5,470
Payment of Contingent Consideration	(620)	0
Adjustment of Contingent Consideration	(642)	33
Ending Balance	4,241	5,503	0
John T Fretz Insurance Agency [Member]
Change in Contingent Consideration Liability [Roll Forward]
Beginning Balance	358	501
Contingent Consideration from New Acquisition	0	0
Payment of Contingent Consideration	(260)	(310)
Adjustment of Contingent Consideration	94	167
Ending Balance	$ 192	$ 358	$ 501