Business Combinations (Estimated Fair Values Of The Aggregate Assets And Liabilities Acquired) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Business Combination, Separately Recognized Transactions [Line Items]
Cash	$ 61,786	$ 5,170
Other current assets	71,637	3,248
Fixed assets	4,766	405
Goodwill	361,118	73,576
Purchased customer accounts	120,603	43,640
Non-compete agreements	233	408
Other assets	1	15
Total assets acquired	620,144	126,462
Other current liabilities	(109,356)	(8,448)
Deferred income taxes, net	(26,423)	(908)
Total liabilities assumed	(135,779)	(9,356)
Net assets acquired	484,365	117,106
Arrowhead General Insurance Agency Superholding Corporation [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash	61,786
Other current assets	69,051
Fixed assets	4,629
Goodwill	322,779
Purchased customer accounts	99,515
Non-compete agreements	100
Other assets	1
Total assets acquired	557,861
Other current liabilities	(107,579)
Deferred income taxes, net	(26,423)
Total liabilities assumed	(134,002)
Net assets acquired	423,859
Arrowhead [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets	180
Fixed assets	25
Goodwill	14,745
Purchased customer accounts	6,490
Non-compete agreements	22
Total assets acquired	21,462
Other current liabilities	(118)
Total liabilities assumed	(118)
Net assets acquired	21,344
Texas Security General Insurance Agency Inc [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets	1,882
Fixed assets	45
Goodwill	10,776
Purchased customer accounts	6,227
Non-compete agreements	14
Total assets acquired	18,944
Other current liabilities	(132)
Total liabilities assumed	(132)
Net assets acquired	18,812
Other [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets	524	879
Fixed assets	67	65
Goodwill	12,818	18,624
Purchased customer accounts	8,371	13,746
Non-compete agreements	97	177
Other assets		2
Total assets acquired	21,877	33,493
Other current liabilities	(1,527)	(846)
Total liabilities assumed	(1,527)	(846)
Net assets acquired	20,350	32,647
Balcos Insurance, Inc., Et Al [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets		187
Fixed assets		20
Goodwill		6,486
Purchased customer accounts		3,530
Non-compete agreements		42
Total assets acquired		10,265
Other current liabilities		(59)
Total liabilities assumed		(59)
Net assets acquired		10,206
Associated Insurance Service, Inc., Et Al [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets		252
Fixed assets		100
Goodwill		9,055
Purchased customer accounts		4,086
Non-compete agreements		92
Total assets acquired		13,585
Other current liabilities		(10)
Total liabilities assumed		(10)
Net assets acquired		13,575
United Benefit Services Insurance Agency, Et Al [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets		438
Fixed assets		20
Goodwill		10,501
Purchased customer accounts		6,787
Non-compete agreements		45
Other assets		4
Total assets acquired		17,795
Other current liabilities		(37)
Total liabilities assumed		(37)
Net assets acquired		17,758
First Horizon Insurance Group, Inc. et al. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash		5,170
Other current assets		1,415
Fixed assets		134
Goodwill		14,701
Purchased customer accounts		8,094
Non-compete agreements		10
Other assets		9
Total assets acquired		29,533
Other current liabilities		(3,790)
Deferred income taxes, net		(908)
Total liabilities assumed		(4,698)
Net assets acquired		24,835
Fitzharris Agency, Inc. et al. [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Other current assets		77
Fixed assets		60
Goodwill		7,244
Purchased customer accounts		3,351
Non-compete agreements		21
Total assets acquired		10,753
Other current liabilities		(3,706)
Total liabilities assumed		(3,706)
Net assets acquired		7,047
Corporate Benefit Consultants, LLC [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Fixed assets		6
Goodwill		6,965
Purchased customer accounts		4,046
Non-compete agreements		21
Total assets acquired		11,038
Net assets acquired		$ 11,038