Deposits - Interest Bearing Deposits (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Interest-bearing Deposit Liabilities, Domestic, by Component [Abstract]
Money market	$ 4,527,448	$ 3,212,889
Savings	703,687	743,742
NOW	0	18,214
Certificates of deposit	5,308,818	4,971,669
Deposits - interest bearing	$ 10,539,953	$ 8,946,514
Year-End Weighted Average Stated Rate
Money market	1.15%	0.65%
Savings	0.81%	0.81%
NOW	0.00%	0.12%
Certificates of deposit	1.00%	1.39%

The aggregate of all domestic and foreign interest-bearing deposit liabilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

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Amount of interest-bearing domestic money market demand account deposit liabilities.

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Amount of interest-bearing domestic negotiable order of withdrawal (NOW) demand deposit liabilities.

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Amount of interest-bearing domestic savings deposit liabilities. Saving deposits bear interest and have no stated maturity.

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Amount of interest-bearing domestic time deposits. Time deposits bear interest for a fixed, stated period of time and include certificate of deposits and individual retirement accounts.

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The weighted average interest rate for domestic money market demand account deposit liabilities.

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The weighted average interest rate for domestic notice of withdrawal demand deposit liabilities.

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The weighted average interest rate for domestic savings deposit liabilities.

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The weighted average interest rate for domestic time deposit liabilities.

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