Income Taxes - Income Tax Expense Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 9,700	$ 12,995	$ 12,979
State	4,035	3,243	3,514
Foreign	2,418	1,476	1,932
Total current	16,153	17,714	18,425
Deferred:
Federal	4,072	(9,425)	8,872
State	1,452	2,749	1,222
Foreign	(250)	72	(596)
Total deferred	5,274	(6,604)	9,498
Income tax expense	$ 21,427	$ 11,110	$ 27,923