PARENT COMPANY CONDENSED FINANCIAL STATEMENTS (Details 3) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Balance sheets
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	164,604,072	164,246,517
Treasury stock, shares (in shares)	20,436,621	20,337,284
Parent Company
Balance sheets
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	164,604,072	164,246,517
Treasury stock, shares (in shares)	20,436,621	20,337,284