Segments - Operating Segment Information (Detail) (USD $)	3 Months Ended		6 Months Ended					3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Subsidiary	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012		Jun. 30, 2014 Reportable Geographical Components [Member] ARIZONA	Jun. 30, 2014 Reportable Geographical Components [Member] ARIZONA	Jun. 30, 2014 Reportable Geographical Components [Member] NEVADA	Jun. 30, 2014 Reportable Geographical Components [Member] NEVADA	Jun. 30, 2014 Reportable Geographical Components [Member] CALIFORNIA	Jun. 30, 2014 Reportable Geographical Components [Member] CALIFORNIA	Jun. 30, 2014 Operating Segments [Member] Specialty Finance Segment [Member]	Jun. 30, 2014 Operating Segments [Member] Specialty Finance Segment [Member]	Jun. 30, 2014 Corporate, Non-Segment [Member]	Jun. 30, 2014 Corporate, Non-Segment [Member]	Dec. 31, 2013 Wholly Owned Subsidiary Banks [Member] Subsidiary
Operating Statistics [Line Items]
Number of wholly-owned subsidiaries			9															3
Cash, cash equivalents and investment securities	$ 1,986,000,000		$ 1,986,000,000					$ 3,000,000	$ 3,000,000	$ 7,000,000	$ 7,000,000	$ 2,400,000	$ 2,400,000	$ 0	$ 0	$ 1,973,600,000	$ 1,973,600,000
Loans, net of deferred loan fees and costs	7,544,567,000		7,544,567,000		6,801,415,000			2,131,000,000	2,131,000,000	1,682,600,000	1,682,600,000	1,694,800,000	1,694,800,000	1,951,500,000	1,951,500,000	84,600,000	84,600,000
Less: allowance for credit losses	(105,937,000)		(105,937,000)		(100,050,000)			(29,900,000)	(29,900,000)	(23,600,000)	(23,600,000)	(23,800,000)	(23,800,000)	(27,400,000)	(27,400,000)	(1,200,000)	(1,200,000)
Total loans held for investment	7,438,630,000		7,438,630,000		6,701,365,000			2,101,100,000	2,101,100,000	1,659,000,000	1,659,000,000	1,671,000,000	1,671,000,000	1,924,100,000	1,924,100,000	83,400,000	83,400,000
Other repossessed assets	59,300,000		59,300,000					13,100,000	13,100,000	24,100,000	24,100,000	0	0	0	0	22,100,000	22,100,000
Goodwill and intangible assets, net	26,500,000		26,500,000					0	0	26,500,000	26,500,000	0	0	0	0	0	0
Other assets	513,200,000		513,200,000					42,200,000	42,200,000	62,700,000	62,700,000	26,200,000	26,200,000	21,100,000	21,100,000	361,000,000	361,000,000
Total assets	10,023,587,000		10,023,587,000		9,307,342,000			2,159,400,000	2,159,400,000	1,779,300,000	1,779,300,000	1,699,600,000	1,699,600,000	1,945,200,000	1,945,200,000	2,440,100,000	2,440,100,000
Deposits	8,469,505,000		8,469,505,000		7,838,205,000			2,115,400,000	2,115,400,000	3,187,800,000	3,187,800,000	2,061,100,000	2,061,100,000	886,300,000	886,300,000	218,900,000	218,900,000
Other borrowings	337,532,000		337,532,000		341,096,000			0	0	0	0	0	0	0	0	337,500,000	337,500,000
Other liabilities	258,900,000		258,900,000					20,900,000	20,900,000	46,800,000	46,800,000	4,800,000	4,800,000	24,700,000	24,700,000	161,700,000	161,700,000
Total liabilities	9,065,923,000		9,065,923,000		8,451,844,000			2,136,300,000	2,136,300,000	3,234,600,000	3,234,600,000	2,065,900,000	2,065,900,000	911,000,000	911,000,000	718,100,000	718,100,000
Allocated equity	957,664,000	799,307,000	957,664,000	799,307,000	855,498,000	759,421,000	[1]	233,700,000	233,700,000	212,500,000	212,500,000	188,700,000	188,700,000	152,300,000	152,300,000	170,500,000	170,500,000
Liabilities and Equity	10,023,587,000		10,023,587,000		9,307,342,000			2,370,000,000	2,370,000,000	3,447,100,000	3,447,100,000	2,254,600,000	2,254,600,000	1,063,300,000	1,063,300,000	888,600,000	888,600,000
Excess funds provided (used)	0		0					210,600,000	210,600,000	1,667,800,000	1,667,800,000	555,000,000	555,000,000	(881,900,000)	(881,900,000)	(1,551,500,000)	(1,551,500,000)
Reconciliation of net income:
Net interest income	93,898,000	82,152,000	184,675,000	158,355,000				29,211,000	55,819,000	29,359,000	57,954,000	24,702,000	47,494,000	16,226,000	30,190,000	(5,600,000)	(6,782,000)
Provision for credit losses	507,000	3,481,000	4,007,000	8,920,000				3,000	1,561,000	(2,011,000)	(2,895,000)	(1,672,000)	(1,017,000)	3,467,000	5,637,000	720,000	721,000
Net interest income (loss) after provision for credit losses	93,391,000	78,671,000	180,668,000	149,435,000				29,208,000	54,258,000	31,370,000	60,849,000	26,374,000	48,511,000	12,759,000	24,553,000	(6,320,000)	(7,503,000)
Non-interest income	5,773,000	11,762,000	10,608,000	16,561,000				934,000	1,754,000	2,352,000	4,641,000	970,000	2,220,000	643,000	725,000	874,000	1,268,000
Non-interest expense	(52,416,000)	(48,531,000)	(102,165,000)	(95,460,000)				(12,793,000)	(26,097,000)	(16,026,000)	(31,262,000)	(13,342,000)	(26,385,000)	(6,640,000)	(13,148,000)	(3,615,000)	(5,273,000)
Income from continuing operations before income taxes	46,748,000	41,902,000	89,111,000	70,536,000				17,349,000	29,915,000	17,696,000	34,228,000	14,002,000	24,346,000	6,762,000	12,130,000	(9,061,000)	(11,508,000)
Income tax expense (benefit)	10,706,000	7,661,000	21,330,000	15,448,000				6,805,000	11,734,000	6,194,000	11,981,000	5,887,000	10,237,000	2,536,000	4,549,000	(10,716,000)	(17,171,000)
Income from continuing operations	36,042,000	34,241,000	67,781,000	55,088,000				10,544,000	18,181,000	11,502,000	22,247,000	8,115,000	14,109,000	4,226,000	7,581,000	1,655,000	5,663,000
Loss from discontinued operations, net	(504,000)	(169,000)	(1,158,000)	(131,000)				0	0	0	0	0	0	0	0	(504,000)	(1,158,000)
Net income	$ 35,538,000	$ 34,072,000	$ 66,623,000	$ 54,957,000				$ 10,544,000	$ 18,181,000	$ 11,502,000	$ 22,247,000	$ 8,115,000	$ 14,109,000	$ 4,226,000	$ 7,581,000	$ 1,151,000	$ 4,505,000

[1] As adjusted, see "Note 10. Income Taxes" to the Unaudited Consolidated Financial Statements.