Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts and other receivables, allowance for uncollectible accounts	$ 2,140	$ 2,555
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	62,612,000	61,826,000
Common stock, shares outstanding	62,612,000	61,826,000