Fair Value Measurements Fair Value Measurements (Details 6) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 145,463	$ 96,424
Interest-earning deposits in financial institutions	115,399	50,998
Available-for-sale Securities	1,539,681	1,494,745
Federal Home Loan Bank stock, at cost	45,602	27,939
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	45,602	27,939
Loans and leases, net	11,492,986	4,230,318
Loans Receivable, Fair Value Disclosure	11,396,792	4,231,078
Servicing Asset		807
Servicing Asset at Fair Value, Amount		807
Deposits, Savings Deposits	6,006,958	4,616,616
Time Deposits	5,516,479	664,371
Deposits, Fair Value Disclosure	5,524,373	665,148
Borrowed Funds	363,672	113,726
Long-term Debt, Fair Value	363,804	113,726
Subordinated debentures	433,545	132,645
Subordinated Debt Obligations, Fair Value Disclosure	417,349	132,498
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	145,463	96,424
Interest-earning deposits in financial institutions	115,399	50,998
Available-for-sale Securities	514	507
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	0	0
Loans Receivable, Fair Value Disclosure	0	0
Servicing Asset at Fair Value, Amount		0
Deposits, Savings Deposits	0	0
Deposits, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	360,000	106,600
Subordinated Debt Obligations, Fair Value Disclosure	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-earning deposits in financial institutions	0	0
Available-for-sale Securities	1,503,858	1,456,334
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	45,602	27,939
Loans Receivable, Fair Value Disclosure	2,366	2,051
Servicing Asset at Fair Value, Amount		0
Deposits, Savings Deposits	6,006,958	4,616,616
Deposits, Fair Value Disclosure	5,524,373	665,148
Long-term Debt, Fair Value	3,804	7,126
Subordinated Debt Obligations, Fair Value Disclosure	417,349	132,498
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-earning deposits in financial institutions	0	0
Available-for-sale Securities	35,309	37,904
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	0	0
Loans Receivable, Fair Value Disclosure	11,394,426	4,229,027
Servicing Asset at Fair Value, Amount		807
Deposits, Savings Deposits	0	0
Deposits, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	0	0
Subordinated Debt Obligations, Fair Value Disclosure	$ 0	$ 0