Fair Value Measurements - Hierarchy (Details) - Fair Value, Measurements, Recurring [Member] - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Assets, Fair Value Disclosure [Abstract]
Total Assets	$ 13,337,000
Liabilities, Fair Value Disclosure [Abstract]
Total Assets, Net		$ 11,223,000
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Total Assets	150,000
Liabilities, Fair Value Disclosure [Abstract]
Total Assets, Net		0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Total Assets	13,187,000
Liabilities, Fair Value Disclosure [Abstract]
Total Assets, Net		11,223,000
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Total Assets	0
Liabilities, Fair Value Disclosure [Abstract]
Total Assets, Net		0
Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Money market funds	150,000
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Money market funds	150,000
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Money market funds	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Money market funds	0
Prepaid Expenses and Other Current Assets [Member] | Interest Rate Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	2,411,000	12,118,000
Prepaid Expenses and Other Current Assets [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Prepaid Expenses and Other Current Assets [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	2,411,000	12,118,000
Prepaid Expenses and Other Current Assets [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Deferred charges and other assets, net [Member] | Interest Rate Swap [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	10,776,000
Deferred charges and other assets, net [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0
Deferred charges and other assets, net [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	10,776,000
Deferred charges and other assets, net [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	$ 0
Other Liabilities [Member] | Interest Rate Swap [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swaps		(895,000)
Other Liabilities [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swaps		0
Other Liabilities [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swaps		(895,000)
Other Liabilities [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swaps		$ 0