Other Income, net - Summary of Other Income, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Other Nonoperating Income (Expense) [Abstract]
Interest and dividend income	$ 1,873		$ 1,625		$ 1,673
Gain on sale and mark-to-market of mutual funds	9,970		8,766		8,087
Change in fair value of earn-out consideration	0		0	[1]	4,060	[1]
Others, net	1,146		968		1,315
Other income, net	$ 12,989	[2]	$ 11,359	[3]	$ 15,135	[3]

[1] Adjusted pursuant to adoption of ASU 2016-18, Statements of Cash Flows, Restricted Cash. Refer to Note 8 and Note 27 to the consolidated financial statements.

[2] Adjusted pursuant to adoption of ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost. Refer to Note 21 and Note 27 to the consolidated financial statements.

[3] These are reclassified to net income and are included in other income, net in the consolidated statements of income. Refer to Note 21 to the consolidated financial statements.