Supplemental Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 2,707	$ 1,304	$ 434
Income taxes paid (refunded) - net	(1,507)	916	(1,130)
Non-cash investing and financing activities:
Reclassification of available-for-sale securities to equity method investment	27,647	0	0
Securities received in exchange for financial instrument obligations	20,007	0	0
Securities delivered in exchange for settlement of financial instrument obligations	520	0	0
Contribution of note payable by non-controlling interest	268	0	0
Restricted stock awards returned in connection with net-share settlement upon vesting	120	0	0
Non-controlling interests recognized in connection with acquisitions	0	2,896	82
Issuance of common stock for acquisition of Sun Well	$ 0	$ 0	$ 60,825