Equity - Narrative (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) director plan shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Jan. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	May 08, 2014 USD ($)
Class of Stock [Line Items]
Number of share-based compensation plans | plan	2
Intrinsic value of options exercised	$ 600,000	$ 7,900,000	$ 18,500,000
Proceeds from exercise of stock options	108,000	3,555,000	11,987,000
Tax benefit from exercise of stock options	200,000	5,900,000	12,500,000
Fair value of options vested	$ 1,400,000	$ 100,000	$ 3,700,000
Granted (in shares) | shares	0	0	0
Total unrecognized compensation expense	$ 0
Share-based compensation expense	12,064,000	$ 14,768,000	$ 21,195,000
Authorized share amount for repurchase			$ 130,000,000	$ 140,000,000	$ 66,000,000	$ 60,000,000	$ 10,000,000
Stock repurchase (in shares) | shares		507,600	5,635,077
Shares repurchased, value		$ 7,600,000	$ 68,300,000
Commissions		0.0	200,000
Adjustments related to tax withholding for share-based compensation	1,474,000	4,914,000	4,082,000
Restricted Stock
Class of Stock [Line Items]
Total unrecognized stock-based compensation related to time-based, nonvested restricted stock	$ 11,400,000
Expenses expected to be recognized over a weighted-average period	1 year 9 months 18 days
Fair value of restricted stock awards vested	$ 5,200,000	$ 17,900,000	$ 17,300,000
Shares repurchased for tax withholding (in shares) | shares	429,918	614,123	419,928
Adjustments related to tax withholding for share-based compensation	$ 1,500,000	$ 4,900,000	$ 4,100,000
Restricted Stock | Minimum
Class of Stock [Line Items]
Vesting period	1 year
Restricted Stock | Maximum
Class of Stock [Line Items]
Vesting period	3 years
Fixed Dollar Value Restricted Stock Units
Class of Stock [Line Items]
Vesting period	1 year
Share-based compensation expense	$ 400,000
Restricted share unit awards granted, fair value	$ 1,600,000
Modified Stock Option
Class of Stock [Line Items]
Contractual term of equity grant	10 years
Share-based compensation expense	$ 400,000
2016 Plan
Class of Stock [Line Items]
Shares authorized for grant under the plan (in shares) | shares	5,000,000
2016 Plan | Stock options
Class of Stock [Line Items]
Vesting period	3 years
Contractual term of equity grant	10 years
2016 Plan | Restricted Stock
Class of Stock [Line Items]
Vesting period	3 years
Members of the Board | Modified Stock Option
Class of Stock [Line Items]
Fully vested options (in shares) | shares	612,000
Number of Board Members with Modified Option Grants | director	7
Former Employee | Modified Stock Option
Class of Stock [Line Items]
Fully vested options (in shares) | shares	278,916