Capital Structure (Details) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended		12 Months Ended
	Oct. 24, 2014	Mar. 25, 2014	Jan. 08, 2013	Dec. 11, 2012	Dec. 31, 2016	Oct. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 21, 2014
Class of Stock [Line Items]
Preferred stock, shares outstanding (shares)					0		0	0
Public offering, common stock shares (shares)				6,249,234
Public offering, by company (shares)				2,500,000
Public offering, by selling shareholders (shares)				3,749,234
Public offering, price per share (usd per share)				$ 6.39
Public offering, net proceeds			$ 4,100	$ 14,700
Additional shares, overallotment option (shares)			687,385
Value of shares issued in business acquisition									$ 1,279	$ 1,472
Repurchases of common stock							$ 3,772	$ 18,071	22,685
Stock option exercises							$ 320	$ 91	$ 2,823
Common stock [Member]
Class of Stock [Line Items]
Shares issued for acquisition, shares									187,620	217,155
Value of shares issued in business acquisition									$ 2
Stock repurchase program, shares authorized for repurchase (shares)	40,000,000.0	20,000,000.0			0	50,000,000	0				10,000,000.0
Share repurchase program, increase in shares authorized (shares)	20,000,000.0	10,000,000.0			10,000,000.0	10,000,000.0
Repurchases of common stock, shares							905,403	4,118,386.000000	3,605,142
Repurchases of common stock							$ 9	$ 41	$ 36
Stock option exercises, shares							90,496	29,128	716,780
Stock option exercises							$ 0	$ 0	$ 7
Maximum [Member]
Class of Stock [Line Items]
Stock option exercises								$ 100