Discontinued Operations - Assets and Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 01, 2018
Carrying amount of major classes of assets included in discontinued operations:
Assets related to discontinued operations, net	$ 2,609,000	$ 163,999,000
Carrying amount of major classes of liabilities included in discontinued operations:
Liabilities related to discontinued operations	0	15,881,000
Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Program development costs		3,300,000
Program development costs, reserves for uncollectible receivables		7,600,000
Disposed of by Sale [Member] | Cole Capital [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment		0
Carrying amount of major classes of assets included in discontinued operations:
Cash	0	2,198,000
Intangible assets, net	0	9,892,000
Other assets, net	0	6,975,000
Goodwill	0	124,812,000
Due from Cole REITs, net	0	1,284,000
Loss recognized on classification as held for sale	0	(19,509,000)
Assets related to discontinued operations, net	0	125,652,000
Held-for-sale or Disposed of by Sale [Member] | Cole Capital [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated amortization		44,100,000
Consideration paid at closing				$ 120,000,000
Loss recognized on classification as held for sale	(1,815,000)	(20,027,000)	$ 0
Estimated costs to sell		500,000
Carrying amount of major classes of liabilities included in discontinued operations:
Accounts payable and accrued expenses	0	14,269,000
Other liabilities	0	1,512,000
Due to Cole REITs	0	100,000
Liabilities related to discontinued operations	$ 0	$ 15,881,000