Equity based compensation (Stock based compensation expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 309	$ 389	$ 573	$ 1,069
Nonvested stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	171	334	307	442
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	129	55	257	285
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	9	0	9	0
Stock purchases [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 0	$ 0	$ 0	$ 342