Leases - Future Minimum Lease Payments for Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leased Assets [Line Items]
2018	$ 7,064
2019	7,167
2020	7,232
2021	4,762
2022	3,042
Thereafter	57,296
Future minimum lease payments for all operating leases	86,563
Operating leases, rent expense	7,400	$ 8,700	$ 3,800
Related Parties
Operating Leased Assets [Line Items]
2018	4,706
2019	4,798
2020	4,860
2021	4,256
2022	2,863
Thereafter	56,653
Future minimum lease payments for all operating leases	78,136
Operating leases, rent expense	4,800	$ 4,200	$ 3,800
Other
Operating Leased Assets [Line Items]
2018	2,358
2019	2,369
2020	2,372
2021	506
2022	179
Thereafter	643
Future minimum lease payments for all operating leases	$ 8,427