Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Benefit Plans
Expenses for plans including contributions	$ 1,617	$ 1,565	$ 1,451
Minimum
Employee Benefit Plans
Number of plans in which employees may participate	1