SELECTED QUARTERLY FINANCIAL DATA (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SELECTED QUARTERLY FINANCIAL DATA (Unaudited)
Interest income	$ 83,856	$ 85,158	$ 71,631	$ 69,269	$ 73,702	$ 75,123	$ 72,890	$ 74,400	$ 309,914	$ 296,115	$ 295,284
Interest expense	(2,598)	(2,869)	(3,158)	(3,576)	(4,099)	(4,352)	(4,477)	(6,720)	(12,201)	(19,648)	(32,643)
Net interest income	81,258	82,289	68,473	65,693	69,603	70,771	68,413	67,680	297,713	276,467	262,641
Negative provision (provision) for credit losses	1,338	4,167	1,842	(3,137)	4,333	2,141	271	6,074	4,210	12,819	(26,570)
FDIC loss sharing income (expense), net	(10,593)	(7,032)	(5,410)	(3,137)	(6,022)	(367)	(102)	(3,579)	(26,172)	(10,070)	7,776
(Loss) gain on sale of securities	(272)			409	1,239				137	1,239
Other-than-temporary-impairment loss on covered securities							(1,115)			(1,115)
Acquisition-related securities gain		5,222							5,222
Other noninterest income	6,939	6,937	5,613	5,568	6,840	6,049	6,088	6,841
Total noninterest income	(3,926)	5,127	203	2,840	2,057	5,682	4,871	3,262	4,244	15,872	31,426
Accelerated vesting of restricted stock	(12,420)								(12,420)
Non-covered OREO expense, net	(25)	88	(80)	(313)	(316)	(1,883)	(130)	(1,821)	(330)	(4,150)	(7,010)
Covered OREO expense, net	594	332	94	813	461	(4,290)	(2,130)	(822)	1,833	(6,781)	(3,666)
Acquisition and integration costs	(4,253)	(5,450)	(17,997)	(692)	(1,092)	(2,101)	(871)	(25)	(28,392)	(4,089)	(600)
Other noninterest expense	(49,984)	(51,170)	(46,233)	(43,991)	(42,578)	(43,383)	(44,454)	(43,629)
Total noninterest expense	(66,088)	(56,200)	(64,216)	(44,183)	(43,525)	(51,657)	(47,585)	(68,895)	(230,687)	(211,662)	(179,993)
Earnings from continuing operations before income taxes	12,582	35,383	6,302	21,213	32,468	26,937	25,970	8,121	75,480	93,496	87,504
Income tax expense	(9,135)	(11,243)	(1,906)	(7,719)	(12,576)	(10,849)	(10,413)	(2,857)	(30,003)	(36,695)	(36,800)
NET EARNINGS FROM CONTINUING OPERATIONS	3,447	24,140	4,396	13,494					45,477	56,801	50,704
Earnings from discontinued operations before income taxes	(578)	39	(81)						(620)
Income tax (expense) benefit	240	(16)	34						258
NET EARNINGS FROM DISCONTINUED OPERATIONS	(338)	23	(47)						(362)
NET EARNINGS	$ 3,109	$ 24,163	$ 4,349	$ 13,494	$ 19,892	$ 16,088	$ 15,557	$ 5,264	$ 45,115	$ 56,801	$ 50,704
Basic earnings per share:
Net earnings from continuing operations (in dollars per share)	$ 0.07	$ 0.53	$ 0.11	$ 0.37					$ 1.09	$ 1.54	$ 1.37
Net earnings (in dollars per share)	$ 0.06	$ 0.53	$ 0.11	$ 0.37	$ 0.54	$ 0.43	$ 0.42	$ 0.14	$ 1.08	$ 1.54	$ 1.37
Diluted earnings per share:
Net earnings from continuing operations (in dollars per share)	$ 0.07	$ 0.53	$ 0.11	$ 0.37					$ 1.09	$ 1.54	$ 1.37
Net earnings (in dollars per share)	$ 0.06	$ 0.53	$ 0.11	$ 0.37	$ 0.54	$ 0.43	$ 0.42	$ 0.14	$ 1.08	$ 1.54	$ 1.37