Related Party Transactions (Details) - NCC [Member]	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Cash contribution for acquisition of membership interest	$ 1,121,000
Office space occupied (in square feet)	59,100
Monthly rent expense (per month)	$ 94,872
Related Party Rent expense	$ 1,122,000	$ 1,035,000	$ 1,016,000