Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the period	$ 39,664	$ 31,735
Net income during the period	26,647	6,929
Treasury stock purchased	(384)
Exercise of stock options	489	746
Balance at end of the period	$ 66,668	$ 39,664