Accounting policies (Details 1)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Retail [Member]
Estimated Fair Value Percentage Segment Reporting Information	100.00%	100.00%
Retail [Member] | Discounted cash flow [Member]
Estimated Fair Value Percentage Segment Reporting Information	50.00%	50.00%
Retail [Member] | Subject company stock price [Member]
Estimated Fair Value Percentage Segment Reporting Information	30.00%	30.00%
Retail [Member] | Guideline public company [Member]
Estimated Fair Value Percentage Segment Reporting Information	10.00%	10.00%
Retail [Member] | Mergers and acquisitions [Member]
Estimated Fair Value Percentage Segment Reporting Information	10.00%	10.00%
Bulk [Member]
Estimated Fair Value Percentage Segment Reporting Information	100.00%	100.00%
Bulk [Member] | Discounted cash flow [Member]
Estimated Fair Value Percentage Segment Reporting Information	50.00%	50.00%
Bulk [Member] | Subject company stock price [Member]
Estimated Fair Value Percentage Segment Reporting Information	30.00%	30.00%
Bulk [Member] | Guideline public company [Member]
Estimated Fair Value Percentage Segment Reporting Information	10.00%	10.00%
Bulk [Member] | Mergers and acquisitions [Member]
Estimated Fair Value Percentage Segment Reporting Information	10.00%	10.00%