Significant Accounting Policies (Details 4) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Summary of changes in accumulated other comprehensive income
Beginning balance accumulated other comprehensive income (loss)	$ 26,986,000	$ 968,000	$ 12,480,000	$ (770,000)
Other comprehensive income (loss) before reclassifications, net of tax	2,207,000	(122,000)	17,876,000	1,616,000
Amounts reclassified from accumulated other comprehensive income	(172,000)		(1,335,000)
Net current period other comprehensive income (loss)	2,035,000	(122,000)	16,541,000	1,616,000
Ending balance accumulated other comprehensive income (loss)	29,021,000	846,000	29,021,000	846,000
Income tax expense included in other comprehensive income	$ 1,400,000	$ 1,100,000	$ 11,400,000	$ 1,100,000