Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	$ 26,781	$ (32,053)
Cash Flows from Investing Activities
Investments purchased	(295,508)	(441,941)
Investments sold	145,314	133,817
Investments called or matured	77,436	329,164
Net change in short-term investments	33,134	(24,746)
Net property and equipment purchased	(8,167)	(4,889)
Net cash used in investing activities	(47,791)	(8,595)
Cash Flows from Financing Activities
Cash dividends paid	(14,062)	(13,150)
Stock plan share issuance	1,545	3,905
Excess tax benefit from exercise of stock options	1,970	884
Net cash used in financing activities	(10,547)	(8,361)
Net decrease in cash	(31,557)	(49,009)
Cash at the beginning of the period	44,314	81,184
Cash at June 30	$ 12,757	$ 32,175