Fair Value Measurements - Hierarchy (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets, Fair Value Disclosure [Abstract]
Total	$ 13,253	$ 13,337
Level 1
Assets, Fair Value Disclosure [Abstract]
Total	0	150
Level 2
Assets, Fair Value Disclosure [Abstract]
Total	13,253	13,187
Level 3
Assets, Fair Value Disclosure [Abstract]
Total	0	0
Money market funds
Assets, Fair Value Disclosure [Abstract]
Money market funds		150
Money market funds | Level 1
Assets, Fair Value Disclosure [Abstract]
Money market funds		150
Money market funds | Level 2
Assets, Fair Value Disclosure [Abstract]
Money market funds		0
Money market funds | Level 3
Assets, Fair Value Disclosure [Abstract]
Money market funds		0
Prepaid expenses and other | Interest rate swaps
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	4,930	2,411
Prepaid expenses and other | Interest rate swaps | Level 1
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Prepaid expenses and other | Interest rate swaps | Level 2
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	4,930	2,411
Prepaid expenses and other | Interest rate swaps | Level 3
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Deferred charges and other assets, net: | Interest rate swaps
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	8,323	10,776
Deferred charges and other assets, net: | Interest rate swaps | Level 1
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	0	0
Deferred charges and other assets, net: | Interest rate swaps | Level 2
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	8,323	10,776
Deferred charges and other assets, net: | Interest rate swaps | Level 3
Assets, Fair Value Disclosure [Abstract]
Interest rate swaps	$ 0	$ 0