Business Segments (Details 1) - USD ($) $ in Thousands		Sep. 30, 2015		Dec. 31, 2014	Sep. 30, 2014	Apr. 07, 2014
Loans and Leases Receivable, Net of Deferred Income		$ 12,452,205		$ 11,882,432
Loans and Leases Receivable, Allowance		(103,271)		(84,455)
Total loans and leases, net		12,348,934		11,797,977
Goodwill		1,728,380		1,720,479
Core deposit and customer relationship intangibles, net		12,704		17,204
Assets		16,814,105		16,234,605
Total deposits		12,115,763		$ 11,755,128
Consolidated Entities [Member]
Loans and Leases Receivable, Net of Deferred Income		12,452,205			$ 11,574,885
Loans and Leases Receivable, Allowance		(103,271)			(81,899)
Total loans and leases, net		12,348,934			11,492,986
Goodwill	[1]	1,728,380			1,722,129
Core deposit and customer relationship intangibles, net		12,704			18,823
Assets		16,814,105			15,938,150
Total deposits		12,115,763			11,523,437
Operating Segments [Member] | Community Banking Segment [Member]
Loans and Leases Receivable, Net of Deferred Income		3,141,576			3,482,125
Loans and Leases Receivable, Allowance		(39,522)			(56,712)
Total loans and leases, net		3,102,054			3,425,413
Goodwill		333,979	[1]		327,728
Core deposit and customer relationship intangibles, net		12,143			17,814
Assets		6,288,790			6,492,674
Total deposits		12,484,050			11,826,681
Operating Segments [Member] | National Lending Segment [Member]
Loans and Leases Receivable, Net of Deferred Income		9,302,580			8,064,868
Loans and Leases Receivable, Allowance		(63,749)			(25,187)
Total loans and leases, net		9,238,831			8,039,681
Goodwill		1,394,401	[1]		1,394,401
Core deposit and customer relationship intangibles, net		561			1,009
Assets		10,418,282			9,182,617
Total deposits		36,586			0
Operating Segments [Member] | Other Segments [Member]
Loans and Leases Receivable, Net of Deferred Income		8,049			27,892
Loans and Leases Receivable, Allowance		0			0
Total loans and leases, net		8,049			27,892
Goodwill		0	[1]		0
Core deposit and customer relationship intangibles, net		0			0
Assets		107,033			262,859
Total deposits		$ (404,873)			$ (303,244)
Capitalsource, Inc. [Member]
Goodwill						$ 1,526,282

[1] The negative balance for total deposits in the “Other” segment represents the elimination of holding company cash held in deposit accounts at the Bank.