Leases (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($) item	Sep. 30, 2019 USD ($) item
Leases
Operating lease option to extend		true
Lease expenses:
Operating leases	$ 3,356	$ 9,817
Short-term leases	213	644
Sublease income	(35)	(94)
Total lease cost	3,534	10,367
Cash payments for operating leases	4,063	11,793
Upon adoption of ASU 2016-02		58,713
New leases	1,929	1,929
Right-of-use assets obtained in exchange for lease obligations	$ 1,929	$ 60,642
Remaining lease term (in year)	5 years 9 months 18 days	5 years 9 months 18 days
Discount rate (as a percent)	4.60%	4.60%
Operating lease liabilities
2020	$ 17,246	$ 17,246
2021	14,754	14,754
2022	12,170	12,170
2023	11,580	11,580
2024	9,123	9,123
Thereafter	17,628	17,628
Total lease payments	82,501	82,501
Less imputed interest	(10,341)	(10,341)
Total	$ 72,160	$ 72,160
Number of operating leases not yet commenced. | item	1	1
Lease expense from leases not yet commenced		$ 1,500
Minimum
Leases
Remaining operating lease term		1 year
Maximum
Leases
Remaining operating lease term		10 years
Operating lease renewal term	5 years	5 years