Unaudited Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Unaudited Consolidated Statements of Cash Flows [Abstract]
Net cash provided by operating activities	$ 34,822	$ 24,242
Investing activities:
Purchases of available-for-sale investments	(273,675)	(268,842)
Purchases of limited partnership interests	0	(1,538)
Proceeds from sales or maturities of available-for-sale investments	302,726	230,272
Net sales (purchases) of short-term investments	(218)	95
Other investing activities	(20,308)	2,113
Net cash provided by (used in) investing activities	8,525	(37,900)
Financing activities:
Dividends paid to shareholders	(11,227)	(11,180)
Net cash used in financing activities	(11,227)	(11,180)
Effect of foreign exchange rates on cash and cash equivalents	(282)	343
Increase (decrease) in cash and cash equivalents	31,838	(24,495)
Cash and cash equivalents at beginning of period	71,549	89,726
Cash and cash equivalents at end of period	$ 103,387	$ 65,231