Industry Segment and Geographic Areas (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets
Revenues	$ 74,323	$ 87,130	$ 81,974	$ 76,233	$ 60,710	$ 69,698	$ 75,148	$ 57,359	$ 319,660	$ 262,915	$ 276,634
Long-lived assets	169,079				115,406				169,079	115,406
Total assets	290,453				218,910				290,453	218,910
United States
Revenues from External Customers and Long-Lived Assets
Revenues									271,045	231,306	245,846
Long-lived assets	133,628				79,556				133,628	79,556
Total assets	236,442				166,171				236,442	166,171
Asia
Revenues from External Customers and Long-Lived Assets
Revenues									10,075	2,229	2,793
Canada
Revenues from External Customers and Long-Lived Assets
Revenues									8,752	3,362	4,147
Europe
Revenues from External Customers and Long-Lived Assets
Revenues									16,001	12,997	9,368
Long-lived assets	15,261				15,286				15,261	15,286
Total assets	31,461				28,920				31,461	28,920
Mexico
Revenues from External Customers and Long-Lived Assets
Revenues									6,636	8,178	9,924
Long-lived assets	20,190				20,564				20,190	20,564
Total assets	22,550				23,819				22,550	23,819
Other
Revenues from External Customers and Long-Lived Assets
Revenues									$ 7,151	$ 4,843	$ 4,556