Number of Restricted Stock Units Issuance As Percentage of Stock Options Granted

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- Definition

Percentage of shares vested

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award Number Of Employees, Forfeitures Threshold

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No definition available.

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- Definition

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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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

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- Definition

The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

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- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

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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- Definition

Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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- Definition

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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- Definition

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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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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No definition available.

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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- Definition

Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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Stock Based Compensation - Additional Information (Detail)			3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 30, 2016	Jun. 08, 2016 shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares	Jun. 01, 2006 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock-based compensation expense \| $			$ 2,140,000	$ 1,652,000	$ 6,725,000	$ 5,334,000
Dividends per share declared \| $ / shares				$ 15.00
Dividend payable, date to be paid				Oct. 03, 2016
Dividend payable, record date				Sep. 22, 2016
Additional compensation cost \| $			400,000		1,600,000
Cash received from options exercised \| $					0	$ 0
Restricted stock unit, unrecognized stock-based compensation cost \| $			$ 15,100,000		$ 15,100,000
Restricted stock unit, weighted-average remaining requisite service period					3 years 2 months 5 days
25% of the shares issued
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive restricted stock unit issued					315,022		415,519	135,440	293,904
Shares granted exercise price \| $ / shares			$ 0		$ 0		$ 0	$ 0	$ 0
Percentage of shares vested					25.00%		25.00%	25.00%	25.00%
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units issuance as percentage of stock options granted	25.00%
RSUs will be forfeited if Purchased Shares does not equal threshold of remaining RSUs from Grant	4
Restricted Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price that equal to up to percentage of the employee's base salary	25.00%
Amended Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option issued			0	0	0	0
Amended Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance										16,000,000
Options granted vesting period					4 years
Amended Plan \| Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted vesting period					10 years
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option issued			0	0	0	0
2016 Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		16,000,000
Options granted vesting period		4 years