Portfolio Loans Covered by Loss Share ("Covered") - Summary of Changes in Accretable Yield for Purchased Loans (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
FDIC loss share receivable		$ 34,319,000	$ 61,475,000	$ 184,554,000
Principal reductions and interest payments	(90,011,000)	(55,736,000)
Summary of Changes in Accretable Yield for Purchased Loans [Roll Forward]
Balance at beginning of period	298,975,000	189,571,000	298,975,000
Accretion	(29,673,000)	(25,320,000)
Reclassifications from nonaccretable difference	8,573,000	7,487,000
Balance at end of period	189,571,000	125,100,000	189,571,000	298,975,000
Loans Purchased From FDIC Outstanding Balance		201,700,000	301,200,000
Net cash proceeds received from FDIC loss share receivable		(10,981,000)	(91,641,000)	(41,415,000)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	(57,639,000)	(41,542,000)
FDIC Indemnification Asset, Period Increase (Decrease)		1,998,000	(4,025,000)
FDIC Indemnification Asset, Accretion of Discount		(13,931,000)	(15,376,000)
Loan impairment recapture		3,977,000	11,242,000
Reductions for payments on Covered assets in excess of expected cash flows		(8,219,000)	(10,735,000)
Contractual Rights [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal reductions and interest payments	(90,011,000)	(55,736,000)
Summary of Changes in Accretable Yield for Purchased Loans [Roll Forward]
Balance at beginning of period	618,791,000	386,966,000	618,791,000
Accretion	0	0
Reclassifications from nonaccretable difference	(1,822,000)	20,358,000
Balance at end of period	386,966,000	266,068,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	(139,992,000)	(85,520,000)
Non-accretable difference [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal reductions and interest payments	0	0
Summary of Changes in Accretable Yield for Purchased Loans [Roll Forward]
Balance at beginning of period	256,481,000	118,627,000	256,481,000
Accretion	0	0
Reclassifications from nonaccretable difference	(72,454,000)	(2,667,000)
Balance at end of period	118,627,000	87,438,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	(65,400,000)	(28,522,000)
Accretable Yield [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal reductions and interest payments	0	0
Summary of Changes in Accretable Yield for Purchased Loans [Roll Forward]
Balance at beginning of period	63,335,000	78,768,000	63,335,000
Accretion	29,673,000	25,320,000
Reclassifications from nonaccretable difference	62,059,000	15,538,000
Balance at end of period	78,768,000	53,530,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	$ (16,953,000)	$ (15,456,000)