Stockholders' Equity - Changes in common shares issued and treasury stock (Details)		9 Months Ended	12 Months Ended
Sep. 30, 2013	Sep. 30, 2013 Common Stock	Dec. 31, 2012 Common Stock	Sep. 30, 2013 Treasury Stock	Dec. 31, 2012 Treasury Stock	Dec. 31, 2011 Treasury Stock
Schedule Of Stockholders Equity [Line Items]
Balance (in shares)	6,261,975	6,261,975	6,259,975	1,005,092	1,005,092	1,005,092
Issuance of shares for common stock grants		0	2,000
Balance (in shares)	6,261,975	6,261,975	6,261,975	1,005,092	1,005,092	1,005,092

Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

No definition available.

Name:	us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration