Acquisitions Business Combination Pro Forma (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Business Combinations [Abstract]
Revenues	$ 77,178	$ 60,687	$ 153,653	$ 117,742
Net income (loss) attributable to common stockholders	$ (14,489)	$ (406)	$ (18,074)	$ 2,891
Basic net income (loss) attributable to common stockholders	$ (0.21)	$ (0.02)	$ (0.29)	$ 0.13
Diluted net income (loss) attributable to common stockholders	$ (0.21)	$ (0.02)	$ (0.29)	$ 0.13