Acquisitions (Schedule of Consolidated Results of Operations) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Acquisitions [Abstract]
Revenue	$ 594,510	$ 661,194
Net income	$ 53,725	$ 27,630
Basic earnings (loss) per share	$ 1.37	$ 0.69
Diluted earnings (loss) per share	$ 1.37	$ 0.69