Notes Payable, Federal Home Loan Bank Advances, Other Borrowings and Subordinated Notes (Narrative) (Detail) (USD $)	3 Months Ended				3 Months Ended				9 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended							3 Months Ended	0 Months Ended	3 Months Ended	12 Months Ended				1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013 subordinated_notes	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2014 Subordinated Debt [Member]	Mar. 31, 2014 Unsecured Debt [Member]	Dec. 31, 2013 Unsecured Debt [Member]	Mar. 31, 2013 Unsecured Debt [Member]	Sep. 30, 2013 Notes Payable to Banks [Member]	Dec. 31, 2013 Notes Payable to Banks [Member]	Mar. 31, 2014 Revolving credit facility	Sep. 30, 2013 Revolving credit facility	Mar. 31, 2014 Securities Sold under Agreements to Repurchase [Member]	Dec. 31, 2013 Securities Sold under Agreements to Repurchase [Member]	Mar. 31, 2013 Securities Sold under Agreements to Repurchase [Member]	Mar. 31, 2014 Borrowings From Banks And Brokers [Member]	Dec. 31, 2013 Borrowings From Banks And Brokers [Member]	Mar. 31, 2013 Borrowings From Banks And Brokers [Member]	Mar. 31, 2014 Fixed Rate Promissory Note [Member]	Mar. 15, 2011 Junior Subordinated Debt [Member]	Mar. 31, 2014 Junior Subordinated Debt [Member]	Dec. 31, 2013 Junior Subordinated Debt [Member]	Dec. 31, 2010 Junior Subordinated Debt [Member]	Dec. 15, 2013 Junior Subordinated Debt [Member]	Dec. 07, 2010 Junior Subordinated Debt [Member]	Nov. 30, 2013 Subordinated Note Due May Twenty Nine Two Thousand And Fifteen [Member]	Mar. 31, 2013 Subordinated Note Due May Twenty Nine Two Thousand And Fifteen [Member]	Mar. 31, 2014 Base Rate Loan [Member] Eurodollar Rate [Member]	Mar. 31, 2014 Base Rate Loan [Member] Federal Funds Rate [Member]	Mar. 31, 2014 Base Rate Loan [Member] Base Rate [Member]	Mar. 31, 2014 Base Rate Loan [Member] Prime Rate [Member]	Mar. 31, 2014 Eurodollar Rate Loan [Member] London Interbank Offered Rate (LIBOR) [Member]	Mar. 31, 2014 Eurodollar Rate Loan [Member] Base Rate [Member]
Debt Instrument [Line Items]
Notes payable	$ 182,000	$ 31,911,000	$ 364,000				$ 364,000	$ 911,000			$ 0
Debt Instrument, Frequency of Periodic Payment						quarterly					quarterly								monthly			quarterly	quarterly
Maturity date						Sep. 30, 2014			Jun. 01, 2015		Nov. 06, 2014	Oct. 25, 2013							Sep. 01, 2017		Dec. 15, 2013		Dec. 15, 2013				May 31, 2015
Contractual rate						1.25%													3.75%					9.50%
Loan agreement with unaffiliated banks, amount				101,000,000					1,000,000
Loan agreement with unaffiliated banks, amount											100,000,000	100,000,000
Proceeds from (Repayments of) Other Debt	(24,018,000)	11,576,000								1,000,000
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum																														3.50%			3.50%
Percentage of commitment fee payment											0.375%
Securities sold under repurchase agreements	211,692,000	224,297,000	235,347,000										31,700,000	55,300,000	44,300,000	180,000,000	180,000,000	180,000,000
Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements													122,100,000			192,100,000
Net Credit Exposure Repurchase Agreements	0
Debt Instrument, Issuance Date																			Aug. 31, 2012		Dec. 31, 2010						Oct. 31, 2005
Other	19,212,000	31,947,000	19,393,000																19,200,000
Junior subordinated notes																									44,700,000
Quarterly principal and interest payments																						4,300,000
Debt Instrument, Initial Payment																				4,600,000
Incremental interest rate over base rate					1.30%	1.00%																						1.50%	1.00%		0.50%	2.50%
Subordinated notes	0	15,000,000	0																								15,000,000
Number of Remaining Subordinated Notes		1
Early Repayment of Subordinated Debt																										$ 10,000,000