Income Taxes - Summary of Income Tax Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, opening balance	$ 1,736	$ 2,129	$ 2,776
Gross increases in tax positions taken in a prior year	187	142	107
Gross increases in tax positions taken in the current year	763	309	236
Lapse of applicable statute of limitations	(704)	(844)	(990)
Unrecognized tax benefits, ending balance	$ 1,982	$ 1,736	$ 2,129