Discontinued Operations (Detail) - Schedule of Discontinued Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Sep. 30, 2011	Sep. 30, 2010
Net interest income	$ 35,089	$ 33,197	$ 31,713	$ 28,252	$ 28,899	$ 29,064	$ 29,416	$ 29,287	$ 30,248	$ 128,251	$ 118,015	$ 126,547
Noninterest income
Other (loss) income					650				503	3,284	2,495	5,095
Total noninterest income					32,770				10,580	76,433	47,495	45,947
Noninterest expense
Salaries and employee benefits					14,511				15,498	61,995	62,981	58,496
Occupancy costs					2,144				2,111	9,747	8,900	8,746
Furniture and equipment					1,870				1,725	7,867	7,044	7,739
Professional services					1,042				1,546	7,158	5,707	4,151
Advertising and marketing					789				554	3,296	3,219	3,073
Goodwill impairment					0					0	630	0
Intangible asset amortization					90				82	1,325	325	328
Other expense					5,026				3,846	20,946	15,182	16,572
Total noninterest expense	35,357	33,029	39,250	28,709	28,886	29,588	28,599	30,145	28,570	136,345	116,902	112,577
Income tax expense from discontinued operations					0					0	6,549	1,581
Net (loss) income from discontinued operations	0	0	0	0	0	(1,804)	(2,724)	935	28	0	(3,565)	2,519
Segment, Discontinued Operations [Member]
Net interest income											24	51
Noninterest income
Insurance income											17,658	25,301
Gain on sale of line of business											5,919	0
Other (loss) income											(3)	(12)
Total noninterest income											23,574	25,289
Noninterest expense
Salaries and employee benefits											12,650	15,533
Occupancy costs											1,842	1,235
Furniture and equipment											810	1,081
Professional services											40	42
Advertising and marketing											119	169
Goodwill impairment											1,871	0
Intangible asset amortization											443	631
Other expense											2,839	2,549
Total noninterest expense											20,614	21,240
Income from discontinued operations before taxes											2,984	4,100
Income tax expense from discontinued operations											6,549	1,581
Net (loss) income from discontinued operations											$ (3,565)	$ 2,519