Income Taxes (Details Textual) (USD $)	3 Months Ended
Mar. 31, 2013
Tax Benefit from Stock Options Exercised	$ 950,000

Tax benefits realized from the exercise of stock options resulting in reductions in the entity's income taxes, which increases net cash provided by operating activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 20

-Section 55

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6576910&loc=d3e11283-113907

Name:	us-gaap_TaxBenefitFromStockOptionsExercised1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration