Stockholders' Equity (Details)
|
3 Months Ended |
|
|
|
|
Mar. 31, 2018
USD ($)
votes
$ / shares
shares
|
Mar. 31, 2017
USD ($)
$ / shares
shares
|
Apr. 26, 2018
USD ($)
|
Dec. 31, 2017
$ / shares
shares
|
Nov. 01, 2016
USD ($)
|
| Class of Stock [Line Items] |
|
|
|
|
|
| Preferred Stock, Shares Authorized | shares |
10,000,000
|
|
|
10,000,000
|
|
| Preferred Stock, Par Value (in usd per share) | $ / shares |
$ 0.0001
|
|
|
$ 0.0001
|
|
| Stock Repurchase Program, Authorized Amount |
|
|
|
|
$ 200,000,000
|
| Stock Repurchased and Retired During Period, Shares | shares |
366,160
|
383,411
|
|
|
|
| Stock Repurchased, Average Cost Per Share | $ / shares |
$ 81.95
|
$ 52.18
|
|
|
|
| Stock Repurchased and Retired During Period, Value |
$ 30,000,000
|
$ 20,000,000
|
|
|
|
| Stock Repurchase Program, Remaining Authorized Repurchase Amount |
$ 70,000,000
|
|
|
|
|
| Stock Repurchased And Retired, Shares | shares |
2,077,105
|
|
|
|
|
| Stock Repurchased And Retired, Value |
$ 130,000,000
|
|
|
|
|
| Class B common stock |
|
|
|
|
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| Class of Stock [Line Items] |
|
|
|
|
|
| Common Stock, Shares Authorized | shares |
75,000,000
|
|
|
75,000,000
|
|
| Common Stock, Par Value (in usd per share) | $ / shares |
$ 0.0001
|
|
|
$ 0.0001
|
|
| Votes per Share Entitled to Share Holder | votes |
10
|
|
|
|
|
| Class A common stock |
|
|
|
|
|
| Class of Stock [Line Items] |
|
|
|
|
|
| Common Stock, Shares Authorized | shares |
750,000,000
|
|
|
750,000,000
|
|
| Common Stock, Par Value (in usd per share) | $ / shares |
$ 0.0001
|
|
|
$ 0.0001
|
|
| Votes per Share Entitled to Share Holder | votes |
1
|
|
|
|
|
| Subsequent Event [Member] |
|
|
|
|
|
| Class of Stock [Line Items] |
|
|
|
|
|
| Stock Repurchase Program, Remaining Authorized Repurchase Amount |
|
|
$ 370,000,000
|
|
|
| Stock Repurchase Program, Increase to Authorized Amount |
|
|
$ 300,000,000
|
|
|