CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2013	$ 405,706	$ 177,775	$ 226,988	$ 943
Beginning balance (in shares) at Dec. 31, 2013		42,846
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,974		22,974
Other comprehensive income (loss)	(3,355)			(3,355)
Excess tax benefits from stock-based compensation	576	$ 576
Stock-based compensation expense	1,460	1,460
Options exercised	9,638	$ 9,638
Options exercised (in shares)		878
Issuance of common stock under Employee Stock Purchase Plans	450	$ 450
Issuance of common stock under Employee Stock Purchase Plans (in shares)		33
Shares surrendered in exchange for payment of payroll tax liabilities	(249)	$ (249)
Shares surrendered in exchange for payment of payroll tax liabilities (in shares)		(16)
Shares surrendered in exchange for the exercise of stock options	(1,941)	$ (1,941)
Shares surrendered in exchange for the exercise of stock options (in shares)		(127)
Ending balance at Dec. 31, 2014	435,259	$ 187,709	249,962	(2,412)
Ending balance (in shares) at Dec. 31, 2014		43,614
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,802		23,802
Other comprehensive income (loss)	(3,075)			(3,075)
Excess tax benefits from stock-based compensation	2,124	$ 2,124
Stock-based compensation expense	2,243	2,243
Options exercised	10,029	$ 10,029
Options exercised (in shares)		858
Issuance of common stock under Employee Stock Purchase Plans	441	$ 441
Issuance of common stock under Employee Stock Purchase Plans (in shares)		23
Shares surrendered in exchange for payment of payroll tax liabilities	(918)	$ (918)
Shares surrendered in exchange for payment of payroll tax liabilities (in shares)		(43)
Shares surrendered in exchange for the exercise of stock options	(3,802)	$ (3,802)
Shares surrendered in exchange for the exercise of stock options (in shares)		(185)
Ending balance at Dec. 31, 2015	$ 466,103	$ 197,826	273,764	(5,487)
Ending balance (in shares) at Dec. 31, 2015	44,267	44,267
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 20,121		20,121
Other comprehensive income (loss)	3,605			3,605
Excess tax benefits from stock-based compensation	669	$ 669
Stock-based compensation expense	2,506	2,506
Options exercised	$ 4,923	$ 4,923
Options exercised (in shares)	362	362
Issuance of common stock under Employee Stock Purchase Plans	$ 694	$ 694
Issuance of common stock under Employee Stock Purchase Plans (in shares)		34
Shares surrendered in exchange for payment of payroll tax liabilities	(86)	$ (86)
Shares surrendered in exchange for payment of payroll tax liabilities (in shares)		(4)
Shares surrendered in exchange for the exercise of stock options	(346)	$ (346)
Shares surrendered in exchange for the exercise of stock options (in shares)		(14)
Ending balance at Dec. 31, 2016	$ 498,189	$ 206,186	$ 293,885	$ (1,882)
Ending balance (in shares) at Dec. 31, 2016	44,645	44,645