Stock-Based Compensation - Stock Appreciation Rights (Details) - Stock Appreciation Rights - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of SAR’s
Awards outstanding, beginning balance (in shares)	1,036,677	1,701,269	2,508,015
Granted (in shares)	0	0	0
Exercised (in shares)	(85,652)	(610,541)	(700,765)
Forfeited (in shares)	(50,723)	(54,051)	(105,981)
Awards outstanding, ending balance (in shares)	900,302	1,036,677	1,701,269
Number of SAR's - SAR's exercisable (in shares)	879,494
Number of SAR's - SAR's expected to vest (in shares)	20,808
Weighted Average Exercise Price (in dollars per share)
SAR's outstanding - beginning balance (in dollars per share)	$ 10.19	$ 10.20	$ 10.22
Granted (in dollars per share)	0	0	0
Exercised (in dollars per share)	10.54	10.13	10.36
Forfeited (in dollars per share)	10.82	11.08	9.66
SAR's outstanding - ending balance (in dollars per share)	10.12	$ 10.19	$ 10.20
Weighted Average Exercise Price - SAR's exercisable (in dollars per share)	10.16
Weighted Average Exercise Price - SAR's expected to vest (in dollars per share)	$ 8.57
Weighted Average Contractual Term - SAR's outstanding	3 years 9 months 18 days	4 years 8 months 12 days	5 years 8 months 12 days
Weighted Average Contractual Term - SAR's expected to vest	3 years 9 months 18 days