Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 35,615	$ 54,528	$ 56,693
Additions	3,182	16,284	28,509
Deductions	(32,488)	(35,197)	(30,674)
Balance at End of Year	6,309	35,615	54,528
Reserve for program development costs [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	7,632	31,652	34,798
Additions	651	9,328	26,191
Deductions	(8,283)	(33,348)	(29,337)
Balance at End of Year	0	7,632	31,652
Reserve for program development costs [Member] | Two Funds Not Yet Offering
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Deductions	(1,300)
Reserve for program development costs [Member] | CCPT V
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Deductions	(32,000)
Allowance for doubtful accounts and other reserves [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	12,683	7,576	6,595
Additions	2,531	6,956	2,318
Deductions	(8,905)	(1,849)	(1,337)
Balance at End of Year	6,309	12,683	7,576
Allowance for doubtful accounts and other reserves [Member] | Discontinued Operations
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at End of Year	1,000
Unsecured note reserve [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	15,300	15,300	15,300
Additions	0	0	0
Deductions	(15,300)	0	0
Balance at End of Year	$ 0	$ 15,300	$ 15,300