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Number of common stock shares received by RSU holder.

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Performance Based Award Performance Percentage

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable within one year (or the operating cycle, if longer).

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-Paragraph 1
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Costs and payments related to employee benefits and equity-based compensation, such as pension expense and contributions, other postretirement benefits expense and payments, stock or unit options expense, and amortization of restricted stock or unit.

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Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of share instruments newly issued under a share-based compensation plan.

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Description of pertinent provisions of equity-based compensation awards that have actual or potential impact upon the company's financial statements.

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Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock compensation expense	$ 36,939	$ 37,449	$ 34,381
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares of common stock that may be issued	11,750,000
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares of common stock that may be issued	4,000,000
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	200,000	100,000	0
Granted, weighted average grant date fair value, per share	$ 28.16	$ 35.20
Awards vested	0
Compensation costs	$ 3,600	$ 2,400
Required performance period	3 years
Performance units vesting conditions	These performance units cliff-vest at the end of a three-year performance period based on achievement of three-year company financial performance targets and strategic initiatives established by the Compensation Committee.
Number of common shares issued in connection with performance units	0
Performance Units [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units performance percentage	0.00%
Performance Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units performance percentage	200.00%
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	1,300,000	1,400,000	1,400,000
Granted, weighted average grant date fair value, per share	$ 27.64	$ 35.08	$ 29.37
Awards vested	1,300,000	1,100,000	1,100,000
Fair value of restricted stock, vested	$ 35,900	$ 37,500	$ 30,800
Compensation costs			4,300
Non-cash stock compensation expense	33,300	35,000	34,400
Unrecognized compensation cost, related to unvested restricted stock, total	$ 31,200
Expected weighted average period to recognize compensation cost on restricted stock and RSUs to be settled in stock (in years)	1 year 5 months 12 days
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	2 years
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	3 years
Restricted Stock Units to be Settled in Cash [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares that may be received by RSU holder	1
Compensation expense related to Restricted Stock Units to be settled in cash	$ 4,000	3,900	3,100
Payments to settle liabilities under compensation plan	4,200	3,100	$ 1,800
Accrued liabilities under Compensation Plan	$ 2,700	$ 2,900
Restricted Stock Units to be Settled in Cash [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	2 years
Restricted Stock Units to be Settled in Cash [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	3 years