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Stockholders' Equity - Common Share Repurchases and Issuances (Detail) - $ / shares | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Equity, Class of Treasury Stock [Line Items] |  |  |  |
Average purchase price per share | $ 12.90 | $ 19.76 | $ 11.45 | $ 20.12
Shares repurchased related to employee stock-based compensation plans | 368,439 | 431,168 | 1,354,712 | 2,075,932
Average purchase price per share | $ 13.05 | $ 19.83 | $ 10.80 | $ 20.65
Common shares issued | 467,007 | 633,170 | 2,966,592 | 4,218,408
Common Stock Shares Outstanding [Member] |  |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |
Common stock repurchased | 13,579,381 | 15,190,685 | 32,789,662 | 29,844,520
Shares repurchased related to employee stock-based compensation plans | 368,439 | 431,168 | 1,354,712 | 2,075,932
Common shares issued | 467,007 | 633,170 | 2,966,592 | 4,218,408

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- Definition For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer. + References No definition available. + Details
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- Definition Number of new stock issued during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 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 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: 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 + Details
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- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: 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 + Details
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