Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Disclosure [Line Items]
Net interest income	$ 28,572	$ 27,163	$ 130,104	$ 137,963
Provision for loan losses	2,083	(140)	13,719	17,503
Refund transfer fees	231	425	78,127	88,071
Mortgage banking income	2,274	1,352	5,591	3,092
Net gain on sales, calls and impairment of securities		301	56	1,929
Bargain purchase gains	26,923		54,726
Other non interest income	5,417	8,398	17,240	20,064
Total non interest income	34,845	10,476	155,740	113,156
Total non interest expenses	29,762	26,438	98,366	97,782
INCOME BEFORE INCOME TAX EXPENSE	31,572	11,341	173,759	135,834
INCOME TAX EXPENSE	10,904	3,471	61,041	47,889
Net income	20,668	7,870	112,718	87,945
Segment end of period assets	3,435,776	3,095,141	3,435,776	3,095,141	3,419,991
Net interest margin	3.54%	3.60%	5.11%	5.60%
Traditional Banking
Segment Reporting Disclosure [Line Items]
Net interest income	28,444	27,059	84,406	78,580
Provision for loan losses	2,543	547	6,505	5,454
Net gain on sales, calls and impairment of securities		301	56	1,929
Bargain purchase gains	26,923		54,726
Other non interest income	5,387	8,367	17,005	19,663
Total non interest income	32,310	8,668	71,787	21,592
Total non interest expenses	26,118	22,065	76,752	67,840
INCOME BEFORE INCOME TAX EXPENSE	32,093	13,115	72,936	26,878
INCOME TAX EXPENSE	11,145	4,293	25,150	8,263
Net income	20,948	8,822	47,786	18,615
Segment end of period assets	3,413,293	3,067,504	3,413,293	3,067,504
Net interest margin	3.54%	3.61%	3.51%	3.48%
Mortgage Banking
Segment Reporting Disclosure [Line Items]
Net interest income	110	100	283	291
Mortgage banking income	2,274	1,352	5,591	3,092
Other non interest income	11	26	27	51
Total non interest income	2,285	1,378	5,618	3,143
Total non interest expenses	851	705	2,928	2,755
INCOME BEFORE INCOME TAX EXPENSE	1,544	773	2,973	679
INCOME TAX EXPENSE	541	270	1,041	237
Net income	1,003	503	1,932	442
Segment end of period assets	8,765	11,810	8,765	11,810
Republic Processing Group
Segment Reporting Disclosure [Line Items]
Net interest income	18	4	45,415	59,092
Provision for loan losses	(460)	(687)	7,214	12,049
Refund transfer fees	231	425	78,127	88,071
Other non interest income	19	5	208	350
Total non interest income	250	430	78,335	88,421
Total non interest expenses	2,793	3,668	18,686	27,187
INCOME BEFORE INCOME TAX EXPENSE	(2,065)	(2,547)	97,850	108,277
INCOME TAX EXPENSE	(782)	(1,092)	34,850	39,389
Net income	(1,283)	(1,455)	63,000	68,888
Segment end of period assets	$ 13,718	$ 15,827	$ 13,718	$ 15,827