Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Interest income	$ 60,788	$ 82,202	$ 130,708	$ 160,236
Interest expense	(27,712)	(39,389)	(58,769)	(80,147)
Net interest income	33,076	42,813	71,939	80,089
Provision for non-covered loan and lease losses	(3,800)	(3,800)	(6,800)	(7,600)
Provision for covered loan and lease losses, net	(1,467)		(8,624)	(549)
Non-interest income (loss)	17,212	16,759	30,181	24,164
Non-interest expenses	(29,006)	(30,696)	(58,092)	(61,475)
Intersegment revenues	0	0	0	0
Intersegment expenses	0	0	0	0
Income before income taxes	16,015	25,076	28,604	34,629
Total assets	6,375,648	7,082,465	6,375,648	7,082,465
Banking [Member]
Segment Reporting Information [Line Items]
Interest income	37,565	29,029	77,229	61,219
Interest expense	(5,765)	(8,404)	(12,297)	(17,884)
Net interest income	31,800	20,625	64,932	43,335
Provision for non-covered loan and lease losses	(3,800)	(3,800)	(6,800)	(7,600)
Provision for covered loan and lease losses, net	(1,467)		(8,624)	(549)
Non-interest income (loss)	(591)	6,637	(113)	13,135
Non-interest expenses	(23,661)	(24,176)	(45,935)	(48,416)
Intersegment revenues	440	311	844	723
Intersegment expenses	0	0	0	0
Income before income taxes	2,721	(403)	4,304	628
Total assets	3,116,655	3,171,839	3,116,655	3,171,839
Wealth Management [Member]
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Interest expense	0	0	0	0
Net interest income	0	0	0	0
Provision for non-covered loan and lease losses	0	0	0	0
Provision for covered loan and lease losses, net	0		0	0
Non-interest income (loss)	5,941	4,624	11,731	9,376
Non-interest expenses	(3,611)	(4,177)	(8,500)	(8,195)
Intersegment revenues	0	0	0	0
Intersegment expenses	(296)	(218)	(605)	(506)
Income before income taxes	2,034	229	2,626	675
Total assets	15,143	14,340	15,143	14,340
Treasury [Member]
Segment Reporting Information [Line Items]
Interest income	23,223	53,173	53,479	99,017
Interest expense	(21,947)	(30,985)	(46,472)	(62,263)
Net interest income	1,276	22,188	7,007	36,754
Provision for non-covered loan and lease losses	0	0	0	0
Provision for covered loan and lease losses, net	0		0	0
Non-interest income (loss)	11,862	5,498	18,563	1,653
Non-interest expenses	(1,734)	(2,343)	(3,657)	(4,876)
Intersegment revenues	0	0	0	0
Intersegment expenses	(144)	(93)	(239)	(217)
Income before income taxes	11,260	25,250	21,674	33,314
Total assets	3,951,720	4,643,788	3,951,720	4,643,788
Major Segment [Member]
Segment Reporting Information [Line Items]
Interest income	60,788	82,202	130,708	160,236
Interest expense	(27,712)	(39,389)	(58,769)	(80,147)
Net interest income	33,076	42,813	71,939	80,089
Provision for non-covered loan and lease losses	(3,800)	(3,800)	(6,800)	(7,600)
Provision for covered loan and lease losses, net	(1,467)		(8,624)	(549)
Non-interest income (loss)	17,212	16,759	30,181	24,164
Non-interest expenses	(29,006)	(30,696)	(58,092)	(61,487)
Intersegment revenues	440	311	844	723
Intersegment expenses	(440)	(311)	(844)	(723)
Income before income taxes	16,015	25,076	28,604	34,617
Total assets	7,083,518	7,829,967	7,083,518	7,829,967
Elimination [Member]
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Interest expense	0	0	0	0
Net interest income	0	0	0	0
Provision for non-covered loan and lease losses	0	0	0	0
Provision for covered loan and lease losses, net	0		0	0
Non-interest income (loss)	0	0	0	0
Non-interest expenses	0	0	0	0
Intersegment revenues	(440)	(311)	(844)	(723)
Intersegment expenses	440	311	844	723
Income before income taxes	0	0	0	0
Total assets	$ (707,240)	$ (747,502)	$ (707,240)	$ (747,502)