Condensed Consolidating Financial Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash provided by (used in) operating activities	$ (24,545)	$ (89,799)
Cash flows from investing activities
Purchase of office facilities	(4,397)	(3,613)
Proceeds from sale of assets	47,562	0
Cash provided by (used in) investing activities	43,165	(3,613)
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock	(4,417)	(4,531)
Repurchase of Class A non-voting common stock for cancellation	(3,832)	(6,618)
Tax deficiency from share-based awards	(751)	(235)
Other financing activities	31,800	88,300
Cash flow provided by (used in) financing activities	17,060	76,916
Net increase (decrease) in cash and cash equivalents	35,680	(16,496)
Cash and cash equivalents, beginning of period	63,364	63,807
Cash and cash equivalents, end of period	99,044	47,311
Dividends paid	5,740	0
Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	(3,832)
Parent Company [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash provided by (used in) operating activities	8,395	11,548
Cash flows from investing activities
Purchase of office facilities	0	0
Proceeds from sale of assets	0
Cash provided by (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	(4,417)	(4,531)
Repurchase of Class A non-voting common stock for cancellation		(6,618)
Tax deficiency from share-based awards	(751)	(235)
Other financing activities	0	0
Cash flow provided by (used in) financing activities	(9,000)	(11,384)
Net increase (decrease) in cash and cash equivalents	(605)	164
Cash and cash equivalents, beginning of period	907	439
Cash and cash equivalents, end of period	302	603
Parent Company [Member] \| Class A Stock [Member]
Cash flows from financing activities
Repurchase of Class A non-voting common stock for cancellation	(3,832)
Guarantor Subsidiaries [Member]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cash provided by (used in) operating activities	27,793	(180)
Cash flows from investing activities
Purchase of office facilities	0	0
Proceeds from sale of assets	0
Cash provided by (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	27,793	(180)
Cash and cash equivalents, beginning of period	2,586	1,557
Cash and cash equivalents, end of period	30,379	1,377
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 provided by (used in) operating activities	(60,733)	(101,167)
Cash flows from investing activities
Purchase of office facilities	(4,397)	(3,613)
Proceeds from sale of assets	47,562
Cash provided by (used in) investing activities	43,165	(3,613)
Cash flows from financing activities
Cash dividends paid on Class A non-voting and Class B voting common stock		0
Tax deficiency from share-based awards	0	0
Other financing activities	31,800	88,300
Cash flow provided by (used in) financing activities	26,060	88,300
Net increase (decrease) in cash and cash equivalents	8,492	(16,480)
Cash and cash equivalents, beginning of period	59,871	61,811
Cash and cash equivalents, end of period	68,363	45,331
Dividends paid	5,740
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 provided by (used in) operating activities	0	0
Cash flows from investing activities
Purchase of office facilities	0	0
Proceeds from sale of assets	0
Cash provided by (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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