Fair Value Measurements Fair Value Measurements (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	$ 11,757,951	$ 4,231,078
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure		2,051
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	11,755,585	4,229,027
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	67,274	51,763
Fair Value, Measurements, Nonrecurring [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	20,766	10,835
Fair Value, Measurements, Nonrecurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	46,508	40,928
Non Purchased Credit Impaired Loans and Leases [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	42,693	40,886
Non Purchased Credit Impaired Loans and Leases [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		0
Loans Receivable, Fair Value Disclosure	0
Non Purchased Credit Impaired Loans and Leases [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring		2,051
Loans Receivable, Fair Value Disclosure	2,366
Non Purchased Credit Impaired Loans and Leases [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	40,327	38,835
Other real estate and foreclosed assets [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	24,015	10,877
Other real estate and foreclosed assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	0	0
Other real estate and foreclosed assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	18,400	8,784
Cost-method Investments [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	566
Cost-method Investments [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	0
Cost-method Investments [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	0
Third party appraisals [Domain] | Non Purchased Credit Impaired Loans and Leases [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	4,178
Third party appraisals [Domain] | Other real estate and foreclosed assets [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	5,615	2,093
Third party appraisals [Domain] | Cost-method Investments [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	$ 566