Stock Repurchase Program (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended	36 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares repurchased as part of stock repurchase programs	4,994,578us-gaap_TreasuryStockSharesAcquired	15,812,566us-gaap_TreasuryStockSharesAcquired	7,185,257us-gaap_TreasuryStockSharesAcquired	27,992,401us-gaap_TreasuryStockSharesAcquired
Cost of shares repurchased	$ 193,434	$ 436,419	$ 125,341	$ 755,194

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the par value method.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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