Equity (Details) - shares
|
3 Months Ended |
6 Months Ended |
18 Months Ended |
Jun. 30, 2019 |
Mar. 31, 2019 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Repurchase of shares |
|
|
|
|
|
|
1,092,529
|
| Exercise of options (in shares) |
|
|
|
|
222,084
|
5,000
|
|
| Class A |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
|
14,424,558
|
|
|
14,424,558
|
|
|
| Balance at end of period (in shares) |
15,381,099
|
|
|
|
15,381,099
|
|
15,381,099
|
| Class B |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
|
53,137,428
|
|
|
53,137,428
|
|
|
| Balance at end of period (in shares) |
52,175,783
|
|
|
|
52,175,783
|
|
52,175,783
|
| Common Stock | Class A |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
15,663,474
|
15,280,833
|
12,899,315
|
|
15,280,833
|
|
|
| Issuance of shares |
975
|
952
|
|
12,810,860
|
|
|
|
| Share conversion - Class B to A (in shares) |
809,179
|
381,689
|
72,195
|
88,455
|
|
|
|
| Balance at end of period (in shares) |
16,473,628
|
15,663,474
|
12,971,510
|
12,899,315
|
16,473,628
|
12,971,510
|
16,473,628
|
| Common Stock | Class B |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
55,014,007
|
55,284,408
|
57,115,842
|
|
55,284,408
|
|
|
| Redesignation of common stock, (in shares) |
|
|
|
57,184,766
|
|
|
|
| Share conversion - Class B to A (in shares) |
(809,179)
|
(381,689)
|
(72,195)
|
(88,455)
|
|
|
|
| Vesting of restricted share grants (in shares) |
4,360
|
39,636
|
16,198
|
14,794
|
|
|
|
| Exercise of options (in shares) |
150,432
|
71,652
|
|
5,000
|
|
|
|
| Fractional shares retired (in shares) |
|
|
|
(263)
|
|
|
|
| Balance at end of period (in shares) |
54,359,620
|
55,014,007
|
57,059,845
|
57,115,842
|
54,359,620
|
57,059,845
|
54,359,620
|
| Common Stock | Pre-IPO |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
|
|
|
57,182,730
|
|
57,182,730
|
57,182,730
|
| Redesignation of common stock, (in shares) |
|
|
|
(57,184,766)
|
|
|
|
| Vesting of restricted share grants (in shares) |
|
|
|
2,036
|
|
|
|
| Treasury Stock | Class A |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
(979,232)
|
(856,275)
|
|
|
(856,275)
|
|
|
| Repurchase of shares |
(113,297)
|
(122,957)
|
(66,112)
|
|
|
|
|
| Balance at end of period (in shares) |
(1,092,529)
|
(979,232)
|
(66,112)
|
|
(1,092,529)
|
(66,112)
|
(1,092,529)
|
| Treasury Stock | Class B |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
(2,176,088)
|
(2,146,980)
|
(2,064,057)
|
|
(2,146,980)
|
|
|
| Redesignation of common stock, (in shares) |
|
|
|
(2,064,057)
|
|
|
|
| Shares withheld related to net settlement of equity awards |
(7,749)
|
(29,108)
|
|
|
|
|
|
| Balance at end of period (in shares) |
(2,183,837)
|
(2,176,088)
|
(2,064,057)
|
(2,064,057)
|
(2,183,837)
|
(2,064,057)
|
(2,183,837)
|
| Treasury Stock | Pre-IPO |
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
| Balance at beginning of period (in shares) |
|
|
|
(2,064,057)
|
|
(2,064,057)
|
(2,064,057)
|
| Redesignation of common stock, (in shares) |
|
|
|
2,064,057
|
|
|
|