Immaterial Corrections to Prior Period Financial Statements (Details) - USD ($)	3 Months Ended		9 Months Ended		36 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Increase in selling, operating and administrative expenses	$ 31,832,000	$ 20,539,000	$ 79,263,000	$ 62,866,000
Decrease in net income	(7,537,000)	(14,306,000)	(33,245,000)	(38,829,000)
Increase in additional paid capital			259,000
Decrease in retained earnings	(22,675,000)		(22,675,000)		$ (16,005,000)
Decrease in non controlling interest	400,696,000		400,696,000		403,983,000
Increase in additional paid-in capital	$ 450,317,000		$ 450,317,000		448,713,000
Restatement Adjustment | Revision of selling, operating and administrative expense
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Increase in selling, operating and administrative expenses		214,000		467,000
Decrease in net income		$ 214,000		$ 467,000
Increase in additional paid capital					1,712,000
Decrease in retained earnings					803,000
Decrease in non controlling interest					909,000
Increase in additional paid-in capital					$ 584,000	$ 575,000	$ 553,000