Derivative Financial Instruments (Embedded derivatives) (Narrative) (Details)		3 Months Ended	12 Months Ended
	Feb. 05, 2016 USD ($) shares	Mar. 31, 2018 shares	Dec. 31, 2017 shares
Derivative [Line Items]
Number of shares to be issued upon conversion (in shares)	73,394	0	0
Number of shares issued upon conversion (in shares)			20,481
Other liabilities
Derivative [Line Items]
Derivative, notional amount | $	$ 2,000,000