CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - shares	3 Months Ended	6 Months Ended		175 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Statement of Stockholders' Equity [Abstract]
Repurchase of common stock (in shares)	1,000,000	23,802	2,346,427	44,153,195