Accrued Expenses and Other Liabilities - Other Non-Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018
Other non-current liabilities
Deferred rent	$ 5,187
Uncertain tax positions	2,274
Deferred acquisition payments	1,524
Asset retirement obligations	914
Other	482
Total other non-current liabilities	$ 10,381				$ 18,492
Accounting Standards Update 2014-09 (Topic 606) [Member]
Other non-current liabilities
Deferred rent					6,442
Uncertain tax positions					4,510
Deferred acquisition payments					4,294
Asset retirement obligations					916
Other					906
Total other non-current liabilities		$ 12,403	$ 16,192	$ 16,833	$ 17,068