Leases - Summary of Maturity Analysis of Operating and Finance Lease Liabilities and Reconciliation of Undiscounted Cash Flows (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Operating lease payments due:
Within one year	$ 1,620
After one but within two years	1,965
After two but within three years	1,603
After three but within four years	1,464
After four but within five years	1,245
After five years	6,691
Total undiscounted cash flows	14,588
Discount on cash flows	(2,160)
Total lease liability	12,428
Finance lease payments due:
Within one year	152
After one but within two years	217
After two but within three years	217
After three but within four years	217
After four but within five years	217
After five years	4,244
Total undiscounted cash flows	5,264
Discount on cash flows	(1,663)
Lease liability	$ 3,601