Capital Structure (Details) (USD $)	0 Months Ended		12 Months Ended			0 Months Ended
	Jan. 08, 2013	Dec. 11, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 24, 2014	Mar. 25, 2014	Feb. 21, 2014
Class of Stock [Line Items]
Preferred stock, shares outstanding			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	$ 4,100,000	$ 14,700,000	$ 0	$ 4,118,000	$ 14,682,000
Additional shares, overallotment option (shares)	687,385
Value of shares issued in business acquisition			1,279,000	1,472,000
Repurchases of common stock			22,685,000
Stock option exercises			2,823,000	916,000	559,000
Common stock [Member]
Class of Stock [Line Items]
Public offering, by company (shares)				687,385	2,500,000
Shares issued for acquisition, shares			187,620	217,155
Value of shares issued in business acquisition			2,000	2,000
Stock repurchase program, shares authorized for repurchase (shares)						40,000,000.0	20,000,000.0	10,000,000.0
Share repurchase program, increase in shares authorized (shares)						20,000,000.0	10,000,000.0
Repurchases of common stock, shares			3,605,142
Repurchases of common stock			36,000	0
Stock option exercises, shares			716,780	202,159	141,849
Stock option exercises			$ 7,000	$ 2,000	$ 2,000