Shareholders' Equity - Additional Information (Detail) - $ / shares shares in Thousands			3 Months Ended	6 Months Ended
	May 05, 2020	May 07, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Class of Stock [Line Items]
Date of declaration of dividends	May 05, 2020	May 07, 2019
Dividend declared per share	$ 0.52	$ 0.50
Date of dividend payment	Jun. 15, 2020	Jun. 17, 2019
Dividends payable to shareholders date of record	Jun. 01, 2020	Jun. 03, 2019
Discretionary Plan
Class of Stock [Line Items]
Expected common stock shares issued and outstanding				160,000
Shares repurchased				4,400	3,110
Average price per share				$ 71.41	$ 73.45
Non-Discretionary Plan
Class of Stock [Line Items]
Shares repurchased			88
Average price per share			$ 74.03