Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax valuation allowance
Balance at beginning of fiscal period	$ 161,160	$ 156,671	$ 153,301
Charges to costs and expenses	0	0	0
Charges to other accounts	5,684	4,489	3,370
Deductions	0	0	0
Balance at end of fiscal period	166,844	161,160	156,671
Allowance for receivables from related parties
Balance at beginning of fiscal period	370	400	400
Charges to costs and expenses	0	0	0
Charges to other accounts	0	0	0
Deductions	(370)	(30)	0
Balance at end of fiscal period	$ 0	$ 370	$ 400