Stock-Based Compensation, Non-Vested Stock Option Activity (Details) - Stock Options - $ / shares	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)	18,774,960	18,858,840	19,016,830
Non-vested options, options granted (in shares)	0	6,106,700	0
Non-vested options, options vested (in shares)	(86,230)	(6,149,060)	(67,920)
Non-vested options, options forfeited (in shares)	(46,030)	(41,520)	(90,070)
Non-vested options at the end of the period (in shares)	18,642,700	18,774,960	18,858,840
Weighted Average Fair Value at Grant Date
Weighted average fair value at the grant date, options outstanding at the beginning of the period (in dollars per share)	$ 12.83	$ 10.73	$ 10.72
Weighted average fair value at grant date, options granted (in dollars per share)	0	16.35	0
Weighted average fair value at grant date, options vested (in dollars per share)	9.04	9.88	8.62
Weighted average fair value at grant date, options forfeited (in dollars per share)	12.27	10.96	10.89
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)	$ 12.85	$ 12.83	$ 10.73