Schedule of Common Stock Repurchases (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Stockholders Equity Note [Abstract]
Shares repurchased	131,414			25,398			193,954	174,211
Cost of shares repurchased	$ 69,989	$ 0	$ 44,268	$ 19,294	$ 12,666	$ 80,486	$ 114,300	$ 112,400
Average price per share repurchased	$ 532.59			$ 759.70			$ 589.10	$ 645.46

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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