Grants and other liabilities (Tables)

6 Months Ended

Jun. 30, 2018

Grants and other liabilities [Abstract]

Grants and other non-current liabilities

	Balance as of June 30,		Balance as of December 31,
	2018		2017
	($ in thousands)
Grants		1,182,650		1,225,877
Other Liabilities		479,729		410,183
Grant and other non-current liabilities		1,662,379		1,636,060