Leases - Summary of minimum future rental payments required (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Operating Leases
2019	$ 4,521
2020	17,149
2021	17,004
2022	16,867
2023	11,055
Thereafter	140,415
Total undiscounted rental payments	207,011
Less imputed interest	(104,124)
Total lease liabilities	102,887
Operating Leases
2019		$ 16,627
2020		17,183
2021		17,124
2022		17,450
2023		11,390
Thereafter		140,562
Total undiscounted rental payments		220,336
Finance Leases
2019	505
2020	2,106
2021	10,440
2022	2,418
2023	0
Thereafter	0
Total undiscounted rental payments	15,469
Less imputed interest	(1,673)
Total lease liabilities	$ 13,796
Finance Leases
2019		2,106
2020		2,106
2021		10,440
2022		2,418
2023		0
Thereafter		0
Total undiscounted rental payments		$ 17,070