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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Percentage of options option becoming vested and exercisable each year.

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Employee Benefits and Incentive Plans - 2006 Executive Incentive Plan and 2013 Long-Term Incentive Plan - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	3 years 8 months 12 days
EIP [Member] \| Prior to 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The annual vesting and exercisable percentage options awarded		20.00%
Option Certificate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The annual vesting and exercisable percentage options awarded		25.00%
Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
The annual vesting and exercisable percentage options awarded	25.00%
Common stock granted under plan	8,500,000
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
Maximum [Member] \| EIP [Member] \| Prior to 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	5 years
Maximum [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	4 years
Maximum [Member] \| Restricted Stock [Member] \| New Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	12 months
Minimum [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	3 years
Minimum [Member] \| Restricted Stock [Member] \| New Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based payment award vesting period	6 months