Earnings Per Share - Shares Repurchased (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	103 Months Ended
	Mar. 31, 2020	Mar. 31, 2020
Schedule Of Shares Repurchased [Line Items]
Total Cost of Shares Repurchased	$ 22,909
Minimum [Member]
Schedule Of Shares Repurchased [Line Items]
Range of Prices Paid Per Share	$ 23.33
Maximum [Member]
Schedule Of Shares Repurchased [Line Items]
Range of Prices Paid Per Share	$ 31.91
2011 Share Repurchase Program [Member]
Schedule Of Shares Repurchased [Line Items]
Total Number of Shares Repurchased	860	7,300