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Stock-Based Compensation and Other Benefit Plans - Textual (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2014	Mar. 31, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 31, 2019
Options granted (in shares)				0
Value of options exercised				$ 1,600,000	$ 2,300,000	$ 1,100,000
Proceeds from options exercised				1,300,000	3,900,000	2,600,000
Tax benefit from compensation expense				1,300,000	1,500,000	1,700,000
Tax benefits from exercise of stock options				$ 300,000	500,000	300,000
Maximum annual contributions per employee (percent)				50.00%
Employer discretionary contribution amount				$ 4,300,000	$ 3,900,000	1,400,000
Restricted Stock [Member]
Estimated fair value at date of grant (in dollars per share)				$ 7.34
Number of performance-based restricted stock units issued, at target (in shares)				104,900
Stock Options [Member]
Vesting period				3 years
Expiration period				10 years
Stock Appreciation Rights (SARs) [Member]
Granted, restricted stock (in shares)					0
Performance-based Restricted Stock Units [Member]
Estimated fair value at date of grant (in dollars per share)				$ 0
Vesting period				3 years
Number of performance-based restricted stock units issued, at target (in shares)				0	0
Allocated share-based compensation expense				$ 100,000	$ 800,000	$ 1,000,000.0
Vested				2,400,000
Restricted stock awards				4,100,000	3,000,000.0
Range of payout of shares for each executive, minimum						0.00%
Range of payout of shares for each executive, maximum						150.00%
Restricted Stock Units and Restricted Stock Awards [Member]
Tax benefit from compensation expense				1,900,000	2,800,000	$ 1,900,000
Allocated share-based compensation expense				9,800,000	7,800,000	8,000,000.0
Restricted stock awards				$ 10,400,000
Period for recognition				2 years 2 months 12 days
Fair value of shares vested				$ 7,200,000	$ 11,600,000	$ 10,400,000
Restricted Stock Units and Restricted Stock Awards [Member] \| Minimum [Member]
Vesting period				3 years
Restricted Stock Units and Restricted Stock Awards [Member] \| Maximum [Member]
Vesting period				4 years
The 2014 Director Plan [Member]
Number of shares authorized (in shares)				1,000,000
Shares available for grant (in shares)				313,780
The 2014 Director Plan [Member] \| Non-employee directors [Member]
Restricted shares granted (in shares)	$ 150,000
The 2014 Director Plan [Member] \| Non-employee directors [Member] \| Restricted Stock [Member]
Granted, restricted stock (in shares)				104,900
Estimated fair value at date of grant (in dollars per share)				$ 7.34
The 2014 Director Plan [Member] \| Board of Directors Chairman [Member]
Restricted shares granted (in shares)	$ 170,000
The 2015 Plan [Member]
Number of shares authorized (in shares)							12,300,000
Shares available for grant (in shares)				3,381,983
The 2015 Plan [Member] \| Employees, non-directors [Member]
Plan modification, expense recognized		$ 4,000,000.0	$ 1,500,000
Participants Contributions from 3 Percent to 6 Percent of Compensation [Member]
Options granted (in shares)				0
Employer matching contribution, percent of match				50.00%
Participants Contributions from 3 Percent to 6 Percent of Compensation [Member] \| Minimum [Member]
Employer matching contribution, percent of employees' gross pay				3.00%
Participants Contributions from 3 Percent to 6 Percent of Compensation [Member] \| Maximum [Member]
Employer matching contribution, percent of employees' gross pay				6.00%
2019 Awards [Member] \| Performance-based Restricted Stock Units [Member]
Allocated share-based compensation expense				$ 2,300,000
2019 Awards [Member] \| Time-based Restricted Stock Units [Member]
Range of payout of shares for each executive, maximum				200.00%
2018 Awards [Member] \| Performance-based Restricted Stock Units [Member]
Allocated share-based compensation expense				$ 1,300,000
2018 Awards [Member] \| Time-based Restricted Stock Units [Member]
Allocated share-based compensation expense				$ 1,300,000
Range of payout of shares for each executive, minimum				0.00%
Range of payout of shares for each executive, maximum				150.00%
2017 Awards [Member] \| Performance-based Restricted Stock Units [Member]
Allocated share-based compensation expense				$ 1,300,000
2017 Awards [Member] \| Time-based Restricted Stock Units [Member]
Allocated share-based compensation expense				$ 5,300,000
Range of payout of shares for each executive, minimum				0.00%
Range of payout of shares for each executive, maximum				150.00%
Participants Contributions Up to 3 Percent of Compensation [Member]
Employer matching contribution, percent of employees' gross pay				3.00%
Employer matching contribution, percent of match				100.00%