Notes Payable - Promissory Note (Details) - USD ($)	1 Months Ended	12 Months Ended			68 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	May 31, 2011
Debt Instrument
Repayments of notes payable		$ 32,404,000	$ 309,000	$ 4,037,000
Promissory Note
Debt Instrument
Maximum borrowings available						$ 1,700,000
Stated interest rate (as a percent)						6.50%
Minimum cash balance						$ 300,000
Proceeds received on borrowings					$ 1,400,000
Repayments of notes payable	$ 479,000