Investments - Schedule of Investments in Limited Partnerships (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Schedule of Cost-method Investments
Total other investments	$ 8,144,000
Other investments, cost	7,763,000
Fair value - partnerships	7,844,000
Unrealized Loss	0
Unrealized Gain	381,000
Other Long-term Investments
Schedule of Cost-method Investments
Other investments, cost	7,763,000	$ 8,057,000
Other Long-term Investments	8,144,000	$ 8,381,000
Limited Partnership
Schedule of Cost-method Investments
Other investments, cost	7,463,000
Fair value - partnerships	7,844,000
Unrealized Loss	0
Unrealized Gain	381,000
Certificates of Deposit
Schedule of Cost-method Investments
Other investments, cost	300,000
Fair value - certificates of deposit	300,000
Unrealized Loss	0
Unrealized Gain	$ 0