Consolidated Statement of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Statement of Other Comprehensive Income [Abstract]
Tax on unrealized holding gain/(loss) on investments arising during period	$ 114	$ (17)
Tax on reclassification adjustments for (gain)/loss on investments included in net income	25	(2)
Tax on unrealized gain (loss) on derivatives arising during the period	45
Tax on reclassification adjustments for gain on derivatives included in net income	$ 45