Rent and Tenant Receivables and Other Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Accounts receivable, net	$ 46,533		$ 46,533		$ 44,798
Straight-line rent receivable	187,721		187,721		161,079
Deferred costs, net	23,374		23,374		26,110
Prepaid expenses	11,981		11,981		9,773
Leasehold improvements, property and equipment, net	17,551		17,551		18,180
Restricted escrow deposits	2,746		2,746		1,190
Deferred tax asset and tax receivable	28,284		28,284		25,287
Program development costs, net	12,115		12,115		12,855
Interest rate swap assets, at fair value	0		0		1,892
Other assets	2,819		2,819		2,473
Total	333,124		333,124		303,637
Allowance for doubtful accounts	7,800		7,800		6,600
Deferred Costs and Other Assets, Net [Member] | Program Development Costs [Member]
Property, Plant and Equipment [Line Items]
Reserves related to program development costs	43,900		43,900		34,800
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Amortization expense	300	$ 400	600	$ 700
Accumulated amortization and depreciation	3,200		3,200		2,600
Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated amortization and depreciation	4,700		4,700		3,700
Depreciation expense	500	500	1,000	1,000
Line of Credit [Member]
Property, Plant and Equipment [Line Items]
Deferred costs, net	9,128		9,128		11,410
Amortization expense	2,600	$ 2,700	5,200	$ 5,500
Accumulated amortization for deferred costs	$ 24,600		$ 24,600		$ 19,400