Condensed Consolidating Financial Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash used in operating activities	$ (41,372)	$ (36,583)
Cash flows from investing activities
Purchase of office facilities	(1,762)	(474)
Cash used in investing activities	(1,762)	(474)
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	(1,476)	(1,511)
Repurchase of Class A non-voting common stock for cancellation	(3,634)	0
Tax deficiency from share-based awards	(741)	(321)
Other financing activities	48,100	42,000
Cash flow provided by (used in) financing activities	42,249	40,168
Net increase (decrease) in cash and cash equivalents	(885)	3,111
Cash and cash equivalents, beginning of period	63,364	63,807
Cash and cash equivalents, end of period	62,479	66,918
Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	(3,634)
Parent Company [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash used in operating activities	5,140	1,394
Cash flows from investing activities
Purchase of office facilities	0	0
Cash used in investing activities	0	0
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	(1,476)	(1,511)
Tax deficiency from share-based awards	(741)	(321)
Other financing activities	0	0
Cash flow provided by (used in) financing activities	(5,851)	(1,832)
Net increase (decrease) in cash and cash equivalents	(711)	(438)
Cash and cash equivalents, beginning of period	907	439
Cash and cash equivalents, end of period	196	1
Parent Company [Member] \| Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	(3,634)
Guarantor Subsidiaries [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash used in operating activities	(2,467)	436
Cash flows from investing activities
Purchase of office facilities	0	0
Cash used in investing activities	0	0
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	0	0
Tax deficiency from share-based awards	0	0
Other financing activities	0	0
Cash flow provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents	(2,467)	436
Cash and cash equivalents, beginning of period	2,586	1,557
Cash and cash equivalents, end of period	119	1,993
Guarantor Subsidiaries [Member] \| Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	0
Non-Guarantor Subsidiaries [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash used in operating activities	(44,045)	(38,413)
Cash flows from investing activities
Purchase of office facilities	(1,762)	(474)
Cash used in investing activities	(1,762)	(474)
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	0	0
Tax deficiency from share-based awards	0	0
Other financing activities	48,100	42,000
Cash flow provided by (used in) financing activities	48,100	42,000
Net increase (decrease) in cash and cash equivalents	2,293	3,113
Cash and cash equivalents, beginning of period	59,871	61,811
Cash and cash equivalents, end of period	62,164	64,924
Non-Guarantor Subsidiaries [Member] \| Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	0
Consolidation, Eliminations [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash used in operating activities	0	0
Cash flows from investing activities
Purchase of office facilities	0	0
Cash used in investing activities	0	0
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	0	0
Tax deficiency from share-based awards	0	0
Other financing activities	0	0
Cash flow provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	$ 0
Consolidation, Eliminations [Member] \| Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	$ 0

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