Cash and Money Market Investments Cash and Money Market Investments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 56,574	$ 68,397
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	478,535	282,248
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	478,535	282,248
Net amount	478,535	282,248
Assets, Total [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	535,678	347,931
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	535,678	347,931
Net amount	529,431	338,491
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	258,401	340,348
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	258,401	340,348
Net amount	258,401	340,348
Liabilities, Total [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	314,975	408,745
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	314,975	408,745
Net amount	275,985	370,098
Derivative Assets Included In Other Assets [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts recognized	57,143	65,683
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	57,143	65,683
Net amount	50,896	56,243
Derivative Liabilities Offsets In Other Assets-Offset [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts offset in the balance sheet	0	0
Net amounts presented in the balance sheet	56,574	68,397
Net amount	17,584	29,750
Derivative Liability, Fair Value, Gross Liability	56,574	68,397
Cash collateral received/pledged [Domain] | Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	0
Cash collateral received/pledged [Domain] | Assets, Total [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	2,210
Cash collateral received/pledged [Domain] | Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	0
Cash collateral received/pledged [Domain] | Liabilities, Total [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	(32,743)	(26,997)
Cash collateral received/pledged [Domain] | Derivative Assets Included In Other Assets [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	2,210
Cash collateral received/pledged [Domain] | Derivative Liabilities Offsets In Other Assets-Offset [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	(32,743)	(26,997)
Types of Financial Instruments [Domain] | Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	0
Types of Financial Instruments [Domain] | Assets, Total [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	(6,247)	(11,650)
Types of Financial Instruments [Domain] | Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	0	0
Types of Financial Instruments [Domain] | Liabilities, Total [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	(6,247)	(11,650)
Types of Financial Instruments [Domain] | Derivative Assets Included In Other Assets [Member] | Assets [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	(6,247)	(11,650)
Types of Financial Instruments [Domain] | Derivative Liabilities Offsets In Other Assets-Offset [Member] | Other Liabilities [Member]
Gain (Loss) on Investments [Line Items]
Gross amounts not offset in the balance sheet	$ (6,247)	$ (11,650)