Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Consolidated Statements of Operations [Abstract]
Stock-based compensation included in general and administrative expense	$ 3,298	$ 3,811	$ 10,537	$ 10,932