Fair Value Measurements - Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Total Assets	$ 18,502	$ 13,337
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Total Assets	0	150
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Total Assets	18,502	13,187
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Total Assets	0	0
Interest rate swap
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	13,925	10,776
Prepaid expenses and other | Interest rate swap | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	4,577	2,411
Prepaid expenses and other | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Prepaid expenses and other | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	4,577	2,411
Prepaid expenses and other | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Deferred charges and other assets, net | Interest rate swap | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	13,925	10,776
Deferred charges and other assets, net | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Deferred charges and other assets, net | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	13,925	10,776
Deferred charges and other assets, net | Interest rate swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	$ 0	0
Money market funds | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Money market funds		150
Money market funds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Money market funds		150
Money market funds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Money market funds		0
Money market funds | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Money market funds		$ 0