Stock-Based Compensation - Schedule of Share-based Compensation, Additional Information (Details) (Stock Options and Restricted Stock Units [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Options and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in usd per share)	$ 1.58	$ 1.35	$ 2.88
Aggregate intrinsic value of options exercised	$ 370,000	$ 9,000	$ 226,000
Total fair value of shares vested	$ 4,895,000	$ 3,564,000	$ 2,340,000