Commitments and Contingencies - Operating Leases (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Future minimum lease payments under noncancellable operating leases - As Lessor
Remainder of 2018	$ 6,675,000		$ 6,675,000
2019	26,569,000		26,569,000
2020	24,839,000		24,839,000
2021	20,117,000		20,117,000
2022	11,340,000		11,340,000
2023 and thereafter	13,594,000		13,594,000
Total future minimum lease payments	103,134,000		103,134,000
Future minimum lease payments under noncancellable operating leases - As Lessee
Remainder of 2018	4,754,000		4,754,000
2019	17,675,000		17,675,000
2020	16,304,000		16,304,000
2021	11,562,000		11,562,000
2022	6,110,000		6,110,000
2023 and thereafter	11,472,000		11,472,000
Total future minimum lease payments	67,877,000		67,877,000
Less imputed lease interest	(15,929,000)		(15,929,000)
Total lease liabilities	51,948,000		51,948,000
Rental expense for all operating lease	3,900,000	$ 3,400,000	11,000,000	$ 10,000,000
Finance obligations	21,300,000		21,300,000		$ 10,400,000
Prepaid rent and security deposit	5,500,000		5,500,000		$ 8,300,000
Gross profit on sale leaseback transactions	6,800,000
Right of use assets obtained in exchange for new operating lease liabilities	21,700,000		23,900,000
Other information of operating leases
Cash payments	$ 3,994		$ 10,617
Weighted average remaining lease term (in years)	4 years 15 days		4 years 1 month 13 days
Weighted average discount rate (as a percent)	12.00%		12.00%
Maximum
Operating Leases
Lease Term - as Lessor			7 years
Lease Term - as Lessee			7 years
Minimum
Operating Leases
Lease Term - as Lessor			6 years
Lease Term - as Lessee			6 years
Sale Leaseback Agreements
Future minimum lease payments under noncancellable operating leases - As Lessee
Finance obligations	$ 72,324,000		$ 72,324,000