SHARE - BASED COMPENSATION - RSUs and PSUs (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
RSUs and PSUs
Underlying Shares
Nonvested restricted stock awards outstanding at beginning of period (in shares)	4,324,000
Granted (in shares)	1,967,000
Vested and exercised (in shares)	(1,150,000)
Forfeited or expired (in shares)	(38,000)
Nonvested restricted stock awarded outstanding at end of period (in shares)	5,103,000
Weighted-Average Grant Date Fair Value
Restricted stock awards outstanding at beginning of period (in dollars per share) | $ / shares	$ 6.62
Granted (in dollars per share) | $ / shares	2.04
Vested and exercised (in dollars per share) | $ / shares	6.89
Forfeited or expired (in dollars per share) | $ / shares	4.95
Restricted stock awarded outstanding at end of period (in dollars per share) | $ / shares	$ 4.81
Unrecognized stock-based compensation expense (in dollars) | $	$ 21.4
Weighted-average amortization period	2 years
PSUs
Underlying Shares
Granted (in shares)	1,072,000
Weighted-Average Grant Date Fair Value
Aggregate grant date fair value (in dollars) | $	$ 2.5
Vesting period	3 years