Leases - Maturities of lease liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Operating Leases Maturities:
2019 (April - December)	$ 7,281
2020	9,605
2021	9,834
2022	10,283
2023	10,409
Thereafter	57,889
Total Lease Payments	105,301
Less: Imputed Interest	35,955
Operating lease liabilities	69,346	$ 70,657
Finance Leases Maturities:
2019 (April - December)	3,561
2020	4,493
2021	4,514
2022	4,639
2023	4,776
Thereafter	39,908
Total Lease Payments	61,891
Less: Imputed Interest	14,695
Finance lease liabilities	$ 47,196