Equity, Non-vested Stock Option Activity (Details) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Status of the Company's non-vested options and changes during the year
Options at the beginning of the period (in shares)	19,289,500
Options granted (in shares)	6,181,700	6,302,100	7,029,600
Options vested (in shares)	(6,244,460)
Options forfeited (in shares)	(209,910)
Options at the end of the period (in shares)	19,016,830	19,289,500
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)	$ 9.73
Weighted average fair value at grant date, options granted (in dollars per share)	12.26	$ 12.82	$ 8.78
Weighted average fair value at grant date, options vested (in dollars per share)	9.18
Weighted average fair value at grant date, options forfeited (in dollars per share)	10.62
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)	$ 10.72	$ 9.73