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Retirement Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employer contribution	6.00%
Employee contribution	80.00%
Plan expense	$ 2,700,000	$ 2,600,000	$ 2,600,000
Retirement Plan expense	0	$ 0
Minimum [Member]
Total annual compensation for a calendar year for non-qualified deferred compensation plan	$ 110,000
Eligibility of participants	1.00%
Maximum [Member]
Eligibility of participants	25.00%

X

- Definition

Deferred Compensation Plan Net Of Contribution Expenses

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No definition available.

+ Details

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X

- Definition

Participant Contribution On Pre Tax Basis Under Retirement Plan

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No definition available.

+ Details

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X

- Definition

Percentage Of Employees Eligible Compensation That Represents Maximum Amount Of Employer Matching Contributions To Four Zero One K Plan

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No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

X

- Definition

Retirement Plan Expense

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No definition available.

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X

- Definition

Total Annual Compensation for a Calendar Year for Non-Qualified Deferred Compensation Plan

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No definition available.

+ Details

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X

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

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No definition available.

+ Details

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X

- Details

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X

- Details

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