Operating Segments (Operating Segments Performance) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 105,346		$ 100,503		$ 209,722		$ 203,056
Provision for loan and covered loan losses	17,038		31,093		44,739		68,671
Non-interest income	26,246		21,592		53,750		45,219
Non-interest expense	83,858		75,664		164,087		151,013
Income (loss) before taxes	30,696		15,338		54,646		28,591
Income tax provision (benefit)	13,192		6,320		22,887		8,599
Net income (loss)	17,504		9,018		31,759		19,992
Noncontrolling interest expense			58	[1]			130	[1]
Net income (loss) attributable to controlling interests	17,504		8,960		31,759		19,862
Assets	12,942,176				12,942,176				12,416,870
Total loans	9,436,235		8,672,642		9,436,235		8,672,642		9,008,561
Deposits	10,734,530				10,734,530				10,392,854
Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	109,517		104,631		218,080		211,308
Provision for loan and covered loan losses	17,038		31,093		44,739		68,671
Non-interest income	21,917		16,854		45,172		35,533
Non-interest expense	73,716		64,322		142,684		128,781
Income (loss) before taxes	40,680		26,070		75,829		49,389
Income tax provision (benefit)	15,395		10,268		29,075		16,424
Net income (loss)	25,285		15,802		46,754		32,965
Net income (loss) attributable to controlling interests	25,285		15,802		46,754		32,965
Assets	11,475,381				11,475,381				11,034,516
Total loans	9,436,235				9,436,235				9,008,561
Deposits	10,851,166				10,851,166				10,542,517
Trust And Investments [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	678		662		1,373		1,264
Non-interest income	4,312		4,722		8,531		9,681
Non-interest expense	4,418		4,829		9,104		9,864
Income (loss) before taxes	572		555		800		1,081
Income tax provision (benefit)	226		221		317		431
Net income (loss)	346		334		483		650
Noncontrolling interest expense			58	[1]			130	[1]
Net income (loss) attributable to controlling interests	346		276		483		520
Holding Company And Other Adjustments [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	(4,849)		(4,790)		(9,731)		(9,516)
Non-interest income	17		16		47		5
Non-interest expense	5,724		6,513		12,299		12,368
Income (loss) before taxes	(10,556)		(11,287)		(21,983)		(21,879)
Income tax provision (benefit)	(2,429)		(4,169)		(6,505)		(8,256)
Net income (loss)	(8,127)		(7,118)		(15,478)		(13,623)
Net income (loss) attributable to controlling interests	(8,127)		(7,118)		(15,478)		(13,623)
Assets	1,466,795	[2]			1,466,795	[2]			1,382,354	[2]
Deposits	$ (116,636)	[2]			$ (116,636)	[2]			$ (149,663)	[2]

[1] During the third quarter 2011, the Company acquired all the noncontrolling interests of our Lodestar subsidiary.

[2] Deposit amounts represent the elimination of Holding Company cash accounts included in total deposits of the Banking segment.