Shareholders' Equity - Summary of Changes in Shareholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 1,898,776	$ 1,466,808	$ 1,808,562	$ 1,605,492
Cumulative-effect adjustment from adoption of ASU 2014-09, net of tax					$ 2,196
Net income	210,209	203,174	398,615	369,223
Purchase of common stock for treasury	(87,980)	(126,296)	(304,479)	(483,538)
Equity-based compensation	18,577	18,595	37,910	28,104
Proceeds from Options exercised	79,857	45,290	178,831	86,094
Ending Balance	2,119,439	1,607,571	2,119,439	1,607,571
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	206	206	206	206
Ending Balance	206	206	206	206
Additional Paid-In-Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,899,100	1,678,100	1,820,223	1,644,197
Equity-based compensation	18,577	18,595	37,910	28,104
Proceeds from Options exercised	79,857	45,290	178,831	86,094
Treasury stock issued upon option exercise and restricted share vesting	(35,378)	(20,289)	(74,808)	(36,699)
Ending Balance	1,962,156	1,721,696	1,962,156	1,721,696
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	7,219,739	6,400,185	7,031,333	6,231,940
Cumulative-effect adjustment from adoption of ASU 2014-09, net of tax					$ 2,196
Net income	210,209	203,174	398,615	369,223
Ending Balance	7,429,948	6,603,359	7,429,948	6,603,359
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(7,220,269)	(6,611,683)	(7,043,200)	(6,270,851)
Purchase of common stock for treasury	(87,980)	(126,296)	(304,479)	(483,538)
Treasury stock issued upon option exercise and restricted share vesting	35,378	20,289	74,808	36,699
Ending Balance	(7,272,871)	(6,717,690)	(7,272,871)	(6,717,690)
Deferred Compensation Trust [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(16,912)	(17,389)	(16,937)	(17,383)
Deferred compensation activity, net	0	241	25	235
Ending Balance	(16,912)	(17,148)	(16,912)	(17,148)
Deferred Compensation Liability [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	16,912	17,389	16,937	17,383
Deferred compensation activity, net	0	(241)	(25)	(235)
Ending Balance	$ 16,912	$ 17,148	$ 16,912	$ 17,148

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Changes in additional paid in capital related to exercise of share-based payments awards (such as stock options) and the amount of recognized equity-based compensation during the period (such as nonvested shares).

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Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Value of stock issued as a result of the exercise of stock options.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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