Stock Options - Schedule of Stock Options Granted (Details) - $ / shares |
3 Months Ended | ||||||||
---|---|---|---|---|---|---|---|---|---|
Mar. 15, 2019 |
Aug. 24, 2018 |
Jan. 05, 2018 |
Mar. 24, 2017 |
Aug. 27, 2015 |
Mar. 31, 2019 |
Mar. 31, 2018 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
Employee Stock Purchase Plan | |||||||||
Shares (in shares) | 38,750 | 160,000 | 25,000 | ||||||
Forfeited (in shares) | (15,250) | 0 | 0 | ||||||
Outstanding (in shares) | 23,500 | 423,700 | 118,500 | 263,700 | 93,500 | ||||
Strike price (in dollars per share) | $ 42.03 | $ 42.01 | $ 45.11 | ||||||
Vesting period (in years) | 5 years | ||||||||
Expiration (in years) | 10 years | ||||||||
Tranche One | |||||||||
Employee Stock Purchase Plan | |||||||||
Shares (in shares) | 80,600 | 50,200 | 12,500 | 46,250 | |||||
Forfeited (in shares) | 0 | 0 | 0 | (4,500) | |||||
Outstanding (in shares) | 80,600 | 50,200 | 12,500 | 41,750 | |||||
Strike price (in dollars per share) | $ 42.01 | $ 46.00 | $ 45.11 | $ 44.21 | |||||
Vesting period (in years) | 3 years | 3 years | 3 years | 3 years | |||||
Expiration (in years) | 10 years | 10 years | 10 years | 10 years | |||||
Tranche Two | |||||||||
Employee Stock Purchase Plan | |||||||||
Shares (in shares) | 79,400 | 99,500 | 12,500 | 23,750 | |||||
Forfeited (in shares) | 0 | 0 | 0 | 0 | |||||
Outstanding (in shares) | 79,400 | 99,500 | 12,500 | 23,750 | |||||
Strike price (in dollars per share) | $ 42.01 | $ 46.00 | $ 45.11 | $ 44.21 | |||||
Vesting period (in years) | 5 years | 5 years | 5 years | 5 years | |||||
Expiration (in years) | 10 years | 10 years | 10 years | 10 years |