Equity - Schedule of Changes in Number of Shares of Common Stock Issued and Repurchased (Detail) - shares
shares in Thousands |
12 Months Ended |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
| Common Stock | Class A |
|
|
|
| Balance at beginning of period (in shares) |
15,281
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Issuance of common stock (in shares) |
4
|
12,811
|
|
| Share conversion - Class B to A (in shares) |
2,815
|
2,467
|
|
| Shares issued under 2018 ESPP (in shares) |
|
3
|
|
| Balance at end of period (in shares) |
18,100
|
15,281
|
|
| Common Stock | Class B |
|
|
|
| Balance at beginning of period (in shares) |
55,284
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Redesignation of common stock, (in shares) |
|
57,185
|
|
| Share conversion - Class B to A (in shares) |
(2,815)
|
(2,467)
|
|
| Vesting of restricted share grants (in shares) |
522
|
215
|
|
| Exercise of options (in shares) |
946
|
351
|
|
| Balance at end of period (in shares) |
53,937
|
55,284
|
|
| Common Stock | Pre-IPO |
|
|
|
| Balance at beginning of period (in shares) |
|
57,182
|
56,505
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Issuance of common stock (in shares) |
|
|
296
|
| Redesignation of common stock, (in shares) |
|
(57,184)
|
|
| Vesting of restricted share grants (in shares) |
|
2
|
389
|
| Equity awards modified to liabilities (in shares) |
|
|
(8)
|
| Balance at end of period (in shares) |
|
|
57,182
|
| Treasury Stock | Class A |
|
|
|
| Balance at beginning of period (in shares) |
(856)
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Repurchase of shares |
(829)
|
(856)
|
|
| Balance at end of period (in shares) |
(1,685)
|
(856)
|
|
| Treasury Stock | Class B |
|
|
|
| Balance at beginning of period (in shares) |
(2,147)
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Redesignation of common stock, (in shares) |
|
(2,064)
|
|
| Repurchase of shares |
|
(83)
|
|
| Shares withheld related to net settlement of equity awards (in shares) |
(509)
|
|
|
| Balance at end of period (in shares) |
(2,656)
|
(2,147)
|
|
| Treasury Stock | Pre-IPO |
|
|
|
| Balance at beginning of period (in shares) |
|
(2,064)
|
(1,720)
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
| Redesignation of common stock, (in shares) |
|
2,064
|
|
| Vesting of restricted share grants (in shares) |
|
|
(344)
|
| Balance at end of period (in shares) |
|
|
(2,064)
|