Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Adoption of Amended Guidance Impact on Previously Reported Quarterly Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement:
Income taxes	$ 37,786		$ 34,517	$ 88,406	$ 87,836
Net income	$ 63,099		$ 57,968	$ 153,257	$ 146,439
Diluted earnings per share	$ 1.78		$ 1.64	$ 4.32	$ 4.16
Diluted weighted-average common shares outstanding	32,650,153		32,498,857	32,601,115	32,469,313
As Reported
Income Statement:
Income taxes		$ 15,508
Net income		$ 34,174
Diluted earnings per share		$ 0.71
Diluted weighted-average common shares outstanding		32,537,225
Balance Sheet:
Paid-in capital		$ 610,285
Cash Flow Statement:
Net cash provided by operating activities		41,852
Net cash used in financing activities		(41,638)
As Adjusted
Income Statement:
Income taxes		14,654
Net income		$ 35,028
Diluted earnings per share		$ 0.74
Diluted weighted-average common shares outstanding		32,546,314
Balance Sheet:
Paid-in capital		$ 609,431
Cash Flow Statement:
Net cash provided by operating activities		42,706
Net cash used in financing activities		$ (42,492)