Loans and Credit Quality (Details Textual) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2014 NonCovered [Member]	Sep. 30, 2013 NonCovered [Member]	Sep. 30, 2014 NonCovered [Member]	Sep. 30, 2013 NonCovered [Member]	Dec. 31, 2013 NonCovered [Member]	Dec. 31, 2013 Nonperforming Financing Receivable [Member] NonCovered [Member]	Sep. 30, 2014 Nonperforming Financing Receivable [Member] NonCovered [Member] Commercial Real Estate Construction Financing Receivable [Member]	Dec. 31, 2013 Nonperforming Financing Receivable [Member] NonCovered [Member] Commercial Real Estate Construction Financing Receivable [Member]	Apr. 07, 2014 Capitalsource, Inc. [Member] NonCovered [Member]	Apr. 07, 2014 Capitalsource, Inc. [Member] Covered [Member]
Financing Receivable, Impaired [Line Items]
Goodwill, Impairment Loss	$ 0	$ (6,600,000)	$ (6,645,000)
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0		0	0
Loans and Leases Receivable, Net of Deferred Income	11,574,885,000		11,574,885,000	4,312,352,000	4,383,393,000	11,223,506,000	3,950,636,000	11,223,506,000	3,950,636,000	3,929,556,000		2,703,000	2,830,000
Business Combination, Acquired Receivables, Fair Value														6,800,000,000	79,200,000
Business Combination, Acquired Receivables, Gross Contractual Amount														9,400,000,000
Loans and Leases Receivable, Gross	11,591,395,000		11,591,395,000	4,313,335,000		11,239,964,000		11,239,964,000		3,930,539,000	46,774,000
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down						236,000	0	236,000	1,100,000
Financing Receivable Recorded Investment Thirty to Eighty Nine Days Past Due	7,400,000		7,400,000	4,200,000		13,269,000		13,269,000		23,897,000
Financing Receivable Recorded Investment Nonaccrual Status Current	61,600,000		61,600,000	37,300,000
Undiscounted Cash Flows Not Expected to be collected														$ 839,800,000