Unaudited Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Unaudited Consolidated Statements of Cash Flows [Abstract]
Net cash provided by operating activities	$ 10,862	$ 22,445
Investing activities:
Purchases of available-for-sale investments	(160,345)	(165,890)
Purchases of limited partnership interests	0	(1,538)
Proceeds from sales or maturities of available-for-sale investments	219,268	147,345
Net sales (purchases) of short-term investments	(25)	329
Other investing activities	(17,396)	2,701
Net cash provided by (used in) investing activities	41,502	(17,053)
Financing activities:
Dividends paid to shareholders	(7,512)	(7,474)
Net cash used in financing activities	(7,512)	(7,474)
Effect of foreign exchange rates on cash and cash equivalents	(481)	(19)
Increase (decrease) in cash and cash equivalents	44,371	(2,101)
Cash and cash equivalents at beginning of period	71,549	89,726
Cash and cash equivalents at end of period	$ 115,920	$ 87,625