Benefit Plans - Summary of Non-vested Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Shares, non-vested, beginning balance (in shares)	1,839,830	2,364,999	3,016,100
Shares, vested (in shares)	(288,394)	(308,373)	(340,362)
Shares, forfeited (in shares)	(66,040)	(216,796)	(310,739)
Shares, non-vested, ending balance (in shares)	1,485,396	1,839,830	2,364,999
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average grant date fair value, non-vested, beginning balance (in dollars per share)	$ 4.60	$ 4.65	$ 4.78
Weighted average grant date fair value, vested (in dollars per share)	4.20	7.51	4.36
Weighted average grant date fair value, forfeited (in dollars per share)	3.50	5.90	6.25
Weighted average grant date fair value, non-vested, ending balance (in dollars per share)	$ 4.73	$ 4.60	$ 4.65